Saturday, July 30, 2011

Nikon Camera Totin' Skeeters

Did I tell you about the mosquito ("skeeter") in Great Smoky Mountains National Park that was soooo big that it tried to take my Nikon D7000 away from me? I'm still shaking when I think about it. I've not even been able to take any good handheld pictures since then. I'm too shaky from remembering the incident.

I found out later that there is a species of mosquito in the Smokies that basically collects cameras. A ranger found quite a cache of Nikons in a hollow tree the other day. They're auctioning them off to benefit Great Smoky Mountains National Park. There were no other brands of camera found besides Nikon. At least they have good taste.

A .45 caliber pistol is the only effective repellent for these dudes. Even Smoky Bear runs from them. You may have seen some of them in the movie Jumanji; you remember, the one with Robin Williams and the weird game. They had captured a couple dozen of them for the movie and trained them. It didn't work out so well, though, 'cause the skeeters stole a car and went on a wild rampage, smashing buildings, other cars, houses, and such. In fact, some of the wreckage in the movie Jumanji was real. They said, what the heck, we might as well film what the skeeters did, since we'll have to pay for it anyway.

Be very careful in the Smokies if you are carrying a Nikon, especially digital. They seem extra interested in the digitals. Maybe it's the EM radiation from the CMOS and CCD imaging sensor chips. And, no matter what, don't come wearing any concoction containing DEET (skeeter nerve agent found in many repellent sprays). These skeeters drink the stuff like soda pop and are quite addicted to it. They'll break your car window to get to the bottle of skeeter repellent.

They seem to hang out around the Tremont area and the middle prong of the Little Pigeon River. Now that I think about it, I haven't seen many of the little pigeons around the river these days!

Keep on capturing time...
Darrell Young

Friday, July 29, 2011

Photography Basics - Understanding Stops, F/Stops, and EV Steps

This article is an excerpt from my upcoming book, Moving Beyond Point-and-Shoot Photography, The Next Step: Learning to Use a DSLR or Interchangeable Lens Camera by Darrell Young. This book aims to teach new DSLR or ILC camera users how to use their more powerful cameras in a superior fashion and assumes no previous knowledge of any aspect of photography. Look for it in March 2012.

What is a Stop?

The term stop is used in photography to represent a relative change in the amount of light that is allowed into the camera.

If you double the light getting into the camera with any of the exposure controls, you have increased the light by one stop. If you reduce the light by half with any of the controls, you have reduced the light by one stop.

What tends to confuse many at first is that the word stop is often used when referring to three different exposure controls: ISO sensitivity, aperture, and shutter speed. Why? Because all three can manage the light that creates the picture. In other words, all three exposure controls allow more or less light into the camera. Adjusting these controls is referred to as “stopping down” (allowing less light let in) or “stopping up” (allowing more light in).

This is an important word to photographers because it gives us an easy way to describe either letting twice as much or half as much light into the camera. One stop up lets in twice as much light, one stop down lets in half as much light.

The phrase stopping down is used much more often in photography writing than the term stopping up. For whatever reason, you’ll more often hear stopping up called opening up instead. The term stop originated in the use of the aperture, but eventually came to mean letting in more or less light.

However you hear or read it, just remember that changing a setting by one stop up (opening or stopping up) lets in twice as much light; changing by one stop down (stopping down) lets in half as much light.

When you read something like, “Let in an extra stop of light,” that simply means doubling the light. If you read, “Take away a stop of light,” it means, cut the light in half. Basically, the term “stop” is a shortcut way of saying “twice as much,” or “half as much” light volume.

If these last few paragraphs seem repetitive, it was on purpose. This is a very important phrase for you to understand!

F/Stops or stops running from f/2.8 to f/16, in this case managed by the aperture control. Each step down cuts light in half, while each step up doubles the light into the camera. The aperture controls how much light comes into the camera, while the shutter speed controls how long light comes into the camera. The ISO sensitivity setting controls how sensitive to light your camera's imaging sensor is. Those three controls are the backbone of controlling exposure. My upcoming  book explains how to use them all together, in an understandable way.

What is an F/Stop?

There is a similar term used in photography that is related directly to how a lens works: the f/stop. This is the origin of the term stop, which is just a shortened form of f/stop. The word stop can have meaning for any of the controls, where f/stop is limited to the aperture control.

Basically, f/stop means the same thing as the word stop, except that it is related to the physical aperture control on your camera. You could interchange the words f/stop or stop when talking about controlling the light with your camera’s aperture. Saying, “Open up one stop” means the same thing as “Open up one f/stop”—let in twice as much light, and vice versa. So when you read the word f/stop, just remember it means the same thing as stop, except it is directly related to the aperture control of the camera, not the shutter speed or ISO sensitivity.

The word f/stop comes from the good old days of having f/numbers (aperture numbers) on a ring at the back of a lens (e.g., f/3.5, f/5.6, f/8). When you turned the aperture ring in one direction you would let in more light, or in the other direction, less light. Most new cameras control the f/stops with a dial you turn on the camera’s body.

What is an EV Step?

Most camera users manuals will also call a stop by yet another name called EV step. EV stands for exposure value, and an EV step is a doubling or halving of light or the equivalent of one stop. 

Whenever you see the words stop, f/stop, or EV step, just realize that they all basically mean the same thing, a doubling or halving of the amount of light getting into the camera. 

Keep on capturing time...
Darrell Young

Wednesday, July 27, 2011

Nikon AF-S Micro Nikkor 40mm f/2.8G Lens for DX – Mini Review

On July 12, 2011 Nikon released a brand new macro lens for DX (only) users. It is an affordable lens, with a suggested retail price of US$279.00. Of course, street prices will often be lower than suggested retail.

 Nikon's AF-S Micro Nikkor 40mm f/2.8G Lens

The AF-S Micro Nikkor 40mm is a small-sized lens with a nice fast aperture and a slightly wide angle view on DX cameras like the Nikon D7000, D300S, D90, D5100, D5000, D3100, and D3000. In fact, since it is an AF-S lens (silent wave motor) with built-in autofocus it will work with all the smaller Nikon cameras like the D3100 and D5100, which have no autofocus motor and depend on the lens to autofocus.

It is able to do 1:1 reproduction without any attachments, which means that you can take high quality stills and close up movies at life-size ratios. If you would like to shoot extreme close ups of things like flowers and collectibles like coins and stamps, this lens is perfect. It has continuous auto or manual focus from 6.4 inches to infinity. At its closest setting it is shooting at a 1X or 1:1 (life-size) ratio. It can also be used for copying old photographs because of its flat-field design (low distortion).

Nikon even recommends the lens for portraits and landscapes. With the large available aperture you have the ability to blur the background for those isolated-subject  shots that are so appealing to us all. The lens has a “rounded” seven-bladed aperture, so it should produce natural-looking bokeh (blurred highlights). In fact, you could even carry the lens as a normal everyday lens for that extreme sharpness and beautiful depth of field only available from the best prime (single focal length) lenses. Since it is a normal lens, it sees approximately what the human eye considers normally-sized subjects on a DX camera.

Here are some of its detailed features:
  • CRC, or Close Range Focusing – The lens uses a floating element design, allowing each lens group to move independently, achieving superior performance when shooting at macro (up close) distances.

  • SWM, or Silent Wave Motor – The lens uses inaudible ultrasonic vibrations to autofocus the lens—providing very smooth and quiet, yet precise, autofocus.

  • SIC, or Super Integrated Coating – The coating on the lens reduces flare and ghosting, helps keeps color consistent, and enhances light transmission.

  • M/A, or Manual/Auto switch – With a macro lens it is very important to have manual focusing ability. Often when focusing at micro distances the depth of field will be so shallow that the focus can only cover a few millimeters of the subject. In extreme close up shooting you may want to use manual focus. All you have to do is flip the M/A switch to M and the lens is ready for your manual focusing. Flip it back to A and autofocus is re-enabled.

Here are the technical specs on the lens:
  • Mount Type :   Nikon F-Bayonet
  • Focal Length : 40mm
  • Maximum Aperture:  f/2.8 
  • Minimum Aperture: f/22 
  • Format: DX 
  • Maximum Angle of View (DX-format): 38°50'
  • Maximum Reproduction Ratio: 1.0x 
  • Lens Elements : 9 
  • Lens Groups: 7 
  • Compatible Format(s) : DX 
  • Diaphragm Blades: 7 
  • Distance Information: Yes 
  • Super Integrated Coating: Yes 
  • Autofocus: Yes 
  • AF-S (Silent Wave Motor): Yes 
  • Minimum Focus Distance: .53ft.(0.163m) 
  • Focus Modes: Auto, Manual, and Manual/Auto 
  • G-type: Yes 
  • Filter Size: 52mm 
  • Accepts Filter Type: Screw-on 
  • Dimensions: (Approx.)2.7x2.5 in. (Diameter x Length), 68.5x64.5mm (Diameter x Length) 
  • Weight: (Approx.)9.9 oz. (280g) 
  • Supplied Accessories: LC-52 52mm Snap-on Front Lens Cap, LF-4 Rear Lens Cap, HB-61 Bayonet Hood, CL-0915 Flexible Lens Pouch

This lens seems to be the answer for those among us who like a small, very portable macro lens. Since it can be used as a normal lens, constantly on the camera instead of a zoom lens, it is certainly good for students of photography that want to make great portraits, landscapes, and close up images with one low-cost, yet high-quality lens.

If you are on a budget, but want superior macro and normal photography, get yourself an AF-S Micro Nikkor 40mm f/2.8G lens.

Keep on capturing time...
Darrell Young

Friday, July 22, 2011

A Visit to Greenbrier in the Smoky Mountains

I have a great fondness for taking pictures in the Smoky Mountains. As far back as I can remember I've been running around the Smokies with my Nikon camera and tripod. Recently, I set out to find a place in the Smokies that I'd never seen. One place that was new to me is Greenbrier, near Gatlinburg.

I've seen all the standard Smoky Mountain sights like Cades Cove and Tremont, and have thousands of pictures to prove it. In the last year or two I've been leaving the Smokies to photograph other areas like the Blue Ridge Parkway and Cherohala Skyway. I took a lot of great pictures in those places but soon felt a hankering to return to "my" mountains, the Great Smokies.

Attached Image

I had never been to Greenbrier since you access it via the Gatlinburg area. Gatlinburg is a great place, but not conducive to taking many nature pictures. Due to the heavy tourist traffic, I generally avoid the area, except for a trip to Roaring Fork Motor Nature Trail from time-to-time.

Attached Image

A friend of mine and I took a drive to Greenbrier to see what sights might await us. I'd been to Tremont in the Smokies quite often, and didn't think a similar place—like Greenbrier—would hold a great deal of interest for me. I was wrong! Not only does Greenbrier offer a beautiful view of the Little Pigeon River cascading down from the mountains, it also offers picnic areas with covered pavilions for groups. I'll take my family back to cook a few hotdogs and burgers while enjoying the sounds and sights of the Greenbrier area.

Attached Image

The Little Pigeon is a famous whitewater river that provides world-class scenic views. As you drive along Greenbrier's gravel road you can watch the scenic river flow outside your left window. It's easy to stop and get a photo or two without ever leaving your car. However, it's much nicer to stop at some of the most impressive waterfalls and climb down the shallow bank to the river's edge. There you can experience the mist and roar of the river first hand. You can close your eyes, listen to the sound and imagine a time up to 1000 years ago, when the Cherokee Indians lived and hunted in this area.

Attached Image

Next time you come to the Smokies, why not set your GPS
to Greenbrier (Lat: N 35° 44.330' — Long: W 83° 24.994') and drive to a peaceful and lovely area for some good times with your family and friends. 

By the way, I took these images with my Nikon D2x and D5000.

Keep on capturing time...
Darrell Young

Tuesday, July 12, 2011

Do Camera Settings Affect RAW (NEF) Files?

This article is an excerpt from my upcoming book, Mastering the Nikon D7000, due out in spring 2011.

Interestingly, a RAW file is not yet an image. It is only "raw" black-and-white information from the camera's sensor, separate color information, and markers for how the camera settings were configured when you took the picture.

When you display a RAW image on your computer in a program like Nikon Capture or View NX2, you are seeing the image displayed with the settings you used at the time you took the picture. However, since a RAW file is not yet an image, none of the settings are permanently applied until you save it as a JPEG or another format.

Proof of this is how easily you can modify the RAW file with a change of settings in the computer software you are using. If you shot it with Cloudy White Balance, you can change it to Shady White Balance and it will be exactly the same as if you shot it originally in Shady instead of Cloudy. If you used the Neutral Picture Control and decide you'd rather use the Vivid Picture Control, change it in the Nikon software and it will be as if you had shot with Vivid in the first place—after you save the image as a different format. You can even save the RAW file with your new settings, but they are still not applied permanently to the image, they are just saved as new markers for later display in-computer.

Since a RAW file does not become an image until it is saved as another format, you can play with it, modify it, or change it as much as you like, and the final result will be as if you used the new settings when you first took the picture.

RAW shooters have learned that RAW (NEF) files are completely flexible and changeable after the fact. Do not worry about what settings you have used on a RAW file, you can change it later. The important thing with RAW files is that you get a correct exposure. That's one thing that cannot be changed after the fact without damaging the appearance of the image. Learn to use your histogram to validate the exposure. Make sure you have correct settings for depth of field (aperture) and motion control (shutter speed), then shoot with abandon as to settings. You can change it all later and it will be as if you used the new settings when you took the picture originally.

No RAW file exists as an image until you save it as a JPEG, TIFF, or other format. Things like noise reduction, white balance, Picture Controls, sharpening, and contrast are applied permanently only at the time the RAW file is saved as something besides a RAW file. RAW files stay raw; that's why RAW (NEF) makes such good storage format and so many experienced photographers shoot with it.

Keep on capturing time...
Darrell Young

Sunday, July 10, 2011

Tamron® SP AF17-50mm F/2.8 XR Di-II VC LD Aspherical (IF) Review

Do you entertain yourself by reading lens reviews and spend hours on eBay looking for the ultimate lens?  Do you have the desire to own every lens ever made?  Does your camera bag weigh more than you do?  Then you may be a good candidate to read this article.

Collecting lenses can be like collecting used Boeing 747 airplanes. They're just plain expensive!  Yet life is best when our camera bags are heavy with glass.  We may not need them today, but they’re there when we do.

Since most of us have lens buying habits approaching national debt levels—it’s a good idea to save money—as long as quality isn’t compromised. Nikkors® have been my choice for most of my photographic life—and will continue to be. Recently, though, several aftermarket lens manufacturers have released very desirable lenses that cost significantly less.  Less is better when it comes to cost!
FIG 1A - Tamron® SP AF17-50mm F/2.8 Lens on a Nikon D300
One of my favorites is the Tamron® SP AF 17-50mm F/2.8 XR Di-II VC LD Aspherical (IF). Although the name is longer than the lens itself, it performs—in certain ways—even better than some of my beloved Nikkors.
The Tamron “SP” designation marks their best lenses with resulting excellence in glass and build quality.

It only costs about $650 USD, which is very reasonable for this level of lens quality and capability. A comparable Nikon-brand lens, such as the AF-S Nikkor 17-55mm F2.8 can cost over twice as much. Of course, the Nikkor lens has a stronger metal build and you pay for that.  The Tamron lens barrel is made of “high-impact” polycarbonate so it can be lighter yet still maintain excellent strength for daily use.

Let me tell you about my experiences with this lens.

Not long after the newest version of the lens was released, I was given an opportunity by and Tamron to use one for a few weeks.  For most of December 2009, this lens was on my Nikon D300s.  I used it as the “portrait” lens while shooting a wedding’s formal groups shots and as a “save my buns” lens when shooting the reception lit by white Christmas tree lights.  Do you know how hard it is for a camera to focus on people dancing by candlelight.  The Tamron’s wide F2.8 constant aperture was a big help. 

Tamron Vibration Compensation (VC) 

The Tamron vibration compensation—called VC—is simply amazing.  Unlike Nikkor’s two-axis vibration reduction (VR), the Tamron has three-axis vibration compensation.  How does VC work?  Well, imagine the difference between a big plus sign “+” and a big “x” letter.  The Nikkor VR system stops vibration in an up/down and left/right direction, like the plus sign.  Tamron VC adds vibration compensation on diagonal movements, like an X.

In other words, not only does it match the Nikkor’s up/down and left/right capability but it also adds diagonal compensation.  Imagine placing an x on top of a + sign, and you’ll see how the VC system can handle camera movements in more directions, up/down, left/right, and diagonally. For this reason, the Tamron does not have a Normal/Active switch, like the newer Nikkor VR lenses.  It handles the other angles automatically and doesn’t need one.

FIG 1B - Tamron® SP AF17-50mm F/2.8 VC Lens

Here’s some rather interesting vibration compensation information provided by Tamron's, technical representative Rob Moody:

Other two-coil systems on the market have to compensate for diagonal movement by triangulating or computing through the body. This is what produces the floating or drifting effect you experience when the stabilization is engaged in other manufacturers lenses. The new three-coil system eliminates this process by using an addition or third coil to compensate for diagonal movement.”

When I’ve depended on VR while using my Nikkors—such as when a tripod is not feasible—I’ve always allowed a second to let the VR “take hold” before taking the picture.  Otherwise background objects can have a weird repeating blur when the VR is not fully locked and the picture is taken.  If you’ve used VR for any length of time, you may know what I mean.  Things on the edges of the image can look really weird, like a failed Photoshop clone effect, even while the subject is sharp.  I attribute this to the VR system not fully acquiring “lockdown,” in a sense, before the shutter is released.

Using the Tamron’s VC system, I didn’t notice this effect at all.  It seemed that the VC was faster at locking down the image.  This is only my opinion, you may find differently.  However, after using Nikkor VR from its earliest versions to the best VR II available today, I’ve grown accustomed to how it works.  The Tamron seems to acquire the subject faster and locks down tighter.

In my opinion, this VC feature alone makes the lens worth the cost.  I handheld this lens in conditions that would make a less competent lens shudder—literally. 

Formal Portrait Work 

I used the Tamron during the formal portrait session in a wedding where I was limited to only two flash units, an SB-800 and a SB-900, with an SU-800 controller and Nikon CLS.  By necessity everything was mostly direct flash.  In FIG 2A, I used one SB-900 with its stock diffuser dome pointing somewhat toward the ceiling, on a Nikon D300s, and was working to control contrast as best I could.
FIG 2A - Bride in front of pastel painting

Within the limitations of this direct-flash portrait, I think the D300s/SB-900/Tamron combination performed quite well.  No forehead or cheek hotspots, only minor shadows, and all detail in whites maintained. The Tamron provided accurate tonal and distance information to my camera and flash, so that exposing the image was effortless.

In FIG 2B, an SB-900 was pointed directly at the group, while a SB-800 was bounced off the white ceiling.  My D300s and SU-800 commander unit, along with the Tamron lens were controlling the exposure.  The combo worked well. 

I’m always afraid to use a new piece of equipment during a wedding, so I was quite wary. However, since this was a digital wedding, I could see any serious problems on the camera’s monitor. I went ahead and used the lens.  From the results seen in FIG 2A and 2B, you can tell that I don’t regret it.
FIG 2B - Bride and bridesmaids
I shot over 100 formal group portraits, with up to 21 people in them, during this wedding. Not a single image was incorrectly focused or badly exposed.  Great lens performance. 

Low Light Performance

During the reception of the wedding, all main lights were turned off, and everyone was dancing to strung-up white Christmas tree lights.  The Tamron was able to acquire focus even under that very low light setting, with the assistance of the SB-900’s infrared beam, of course.  I tried shooting these dark images with my AF-S Nikkor 16-85mm, but could not seem to get good autofocus.  I quickly switched to the Tamron, with its constant F/2.8 aperture and that did the trick.  However, the proof in the pudding is whether or not the full combination of camera, flash, and lens can provide accurate exposure under very difficult conditions.
FIG 2C - Bride and Groom
FIG 3 shows an example of the type of image I was able to capture shooting basically in the dark.  In the background of the image you can see the tiny lights that were used to provide a romantic atmosphere for the dancing.  The bride and groom were dancing and spinning, while I was doing my best to capture them for posterity.  The lens, once again, gave the camera and flash correct information for balanced exposure, with no blowout of whites or skin tones.  The lens/camera/flash let the darks suffer, and kept the bride and groom exposed well.  That’s awfully hard to do.

Of course, in an image with this level of darkness, you expect to see some shadows go fully black, but the important bits were exposed correctly, and the image’s histogram just touched the highlight side of the histogram window.  Under these conditions, that’s quite admirable performance from the combination.  The Tamron can be trusted to deliver.

Now, let’s look at some technical information for this fine lens.

Technical Information  (for Model B005)

The Tamron® SP AF17-50mm F/2.8 XR Di-II VC LD Aspherical (IF) lens is designed for use on a Nikon having a DX imaging sensor.  It does not provide a large enough image circle to cover the size of an FX sensor, so it won’t work on a D700 or D3s/x.  It’ll work fine on all DX models from the Nikon D40 to D300s.  Here is an acronym list explaining what all the symbols applying to this lens mean:

Acronyms for Tamron® SP AF17-50mm F/2.8 XR Di-II VC LD Aspherical (IF) (Model B005)
  • SP = Super Performance.  Tamron’s best lenses.
  • AF = Autofocus
  • XR = Extra Refractive Index.  Allows smaller lens diameter due to stronger refraction in front elements.
  • Di-II = Digitally Integrated.  Designed for DX sensors (APS-C or 24x16mm).
  • VC = Vibration Compensation.  Reduces handheld vibrations in three planes.
  • LD = Low Dispersion.  Lens contains one or more elements that achieve apochromatic performance.
  • IF = Internal Focusing.  The length of the lens does not change during focus.
  • BIM = Built-in Motor.  Will work on smaller Nikons with no in-body lens AF motor.
As mentioned in the acronym list, the newest version of this lens (model B005) has a built-in autofocus motor (BIM), so it will work on the smaller Nikon bodies like the D40, D60, D3000, or D5000.

Lens Sharpness

I read a review at about this lens, and they were rating it as having comparable sharpness from F/2.8 to F/11.  I had a hard time believing this until I shot the images in FIG 4.  I cut these sample segments out from an area between the middle and edge of the images.
FIG 4 - Testing for lens sharpness
 I can honestly state that the lens performs nearly as well wide open as at any aperture down to F/11.  The reason I say nearly, is that I note some mild edge softness and slight light falloff in the corners at F/2.8.  It’s gone by F/4.  That’s to be expected in most all lenses.

The absolute best sharpness is found at F/8 to F/11, but is entirely usable across all apertures.  If you look closely at FIG 4, you’ll see a lessening in sharpness at F/16 as diffraction starts to take its toll.  However, I would feel comfortable using this lens at any aperture.  This is a sharp one, for sure! 

Lens Distortion

To test for distortion I shot against a concrete brick wall at various apertures.  I tried to walk closer or farther away to keep the blocks somewhat close to the same size, so that they’re easier to compare.

FIG 5 - Testing for lens distortion

I note some barrel distortion at 17mm, but by 24mm it seems to be gone.  Since the focal range on this lens is so short, it is easier to control for distortion.  I really can’t see any distortion between 24mm and 50mm. 

Lens Flare

What’s the worst case scenario for a lens?  To be pointed directly into the sun.  I gave this lens the acid test by standing in the superstore parking lot and including the sun in the image (see FIG 6).

FIG 6 - Testing for lens flare and contrast

As expected you can see the teardrop shaped rainbow effect chromatic flare in the lower right corner.  In fact, if you look closely the greenish flare extends all the way from the left bottom corner to the sun.  However, I’ve seen few lenses that don’t give you this effect, and it’s even added in movies sometimes since we are all so used to seeing it. The nice thing about this lens is that it maintained high contrast in the rest of the image. There is no milky effect that lowers the contrast of the entire image. The only areas affected by the sun are the actual flare reflections. The rest of the image is still high contrast and sharp.

I would consider this good reflection control and shows that the lens has good quality coatings on its elements.  Otherwise, an image with the sun in it would be very low contrast as the light bounces around between the elements. 

Light Falloff

I was impressed with this lens’ minimal light falloff.  I use a Nikkor 16-85mm and battle relatively worse light falloff.  There is some light falloff at maximum aperture and shortest focal length (see FIG 7).

FIG 7 - Testing for light fallof

F/2.8 shows falloff it in the corners, but it is mostly gone by F/4. The only time I could really detect light falloff was at 17mm and F/2.8 and F/4. At any other focal length besides 17mm I could not detect any significant light falloff. There was just a tiny bit at 24mm and F/2.8. What you see in FIG 7 is “worst case scenario” in my opinion. This lens does not have serious light falloff problems, and what it does have is easily corrected in software. 

Chromatic Aberration

To test for Chromatic Aberration (CA) with the Nikon D300s is a little more difficult than with some cameras.  The D300s automatically removes CA when creating a JPEG.  So, I shot this backlit tree on the left in FIG 8 in RAW instead, and processed it through Nikon Capture NX2 with “Lateral Chromatic Aberration” correction turned off.

FIG 8 - Testing for lens chromatic aberration (CA)

The results were what I would call excellent. In FIG 8 you can see the red opaque area of the big image represented at 100% on the right. Even at 500% I could not detect significant amounts of CA. This is a worst case scenario, too.  Backlit tree limbs will show CA when it is present, in my experience.  Can you see any?  I can’t! 

Sample Images from Tamron

Now let’s look at three larger sample images.  One of them I took in Knoxville Tennessee at the colorful front of a bankrupt Circuit City store.  The other two were provided by Tamron, since I did not have the lens during a colorful season (December) and couldn’t get any beauty-in-nature shots.  The two nature shots were taken by Tamron technical representative Rob Moody personally.  He was using his Nikon D700 in DX mode (5.5mp).

FIG 9 – Architectural Example – Nikon D300s, Tamron 17-50mm F/2.8 VC, 1/250s at F/9, ISO 100 - © Darrell Young
FIG 10 – Loch Raven – Nikon D700 (DX Mode), Tamron 17-50mm F/2.8 VC, 1/800s at F/5.6, ISO 500 - © Rob Moody
FIG 11 – Reflection – Nikon D700 (DX Mode), Tamron 17-50mm F/2.8 VC, 1/80s at F/6.3, ISO 200 - © Rob Moody

Some Basic Lens Facts
  • The lens uses a normal non-ultrasonic autofocus motor, but the focus is fast and quiet.  I had no AF seeking issues, even in an extremely dark environment.
  • The end of the lens does not rotate during autofocus, so you can use your polarizer without difficulty.
  • The maximum aperture is a constant F/2.8 all through the zoom range.
  • It has 14 groups with a total of 19 elements.
  • It’s angle of view is 78°45’ to 31°11’ (APS-C equivalent)
  • It has 7 aperture blades for a nearly circular opening
  • The minimum aperture is F/32
  • The minimum focusing distant is 11.4 inches (0.29m)
  • The maximum macro magnification is 1:4.8
  • Its filter diameter is 72mm
  • The lens weighs 20.15 ounces (570g)
  • It is 3.13 inches (76.5mm) in diameter and 3.7 inches (94mm) long.
  • It comes with a 72mm flower-shaped lens hood
  • It has a 6-year limited warranty in the USA
  • Earlier versions of this lens have won EISA’s Best Product Award, American Photo’s Editor’s Choice Award, and Professional Photographer’s HOT ONE Winner award.
A Look at this Lens
Here are a few images of the lens from different angles.  This is one good looking lens; don’t you agree?  It takes pictures even better than it looks!
FIG 12 – Tamron 17-50mm F/2.8 VC various views

My Conclusions

I would feel confident using this lens in almost any situation.  It feels strong and robust, with a design and warranty showing that it’s made for many years of usage.  While not up to the heavy standard of a metal Nikkor lens, it doesn’t cost nearly as much either.  For a photographer that needs a good solid high-performance lens, but has to maintain a budget, this lens performs extremely well.

I love the constant F/2.8 maximum aperture.  This lets me use the lens to isolate my subjects with shallow depth of field when wide open, and have plenty of depth when stopped down.  It’s surprisingly sharp wide open.  The specs I’ve read on other more technical reviews show very similar sharpness results from F/2.8 to F/11, and some minor sharpness loss due to defraction between F/16 and F/32.  Quite an impressive lens!  It’s highly corrected and acceptable wide open, which is unusual in a lens of this price range.

I read a review of an earlier version of this lens on Popular Photography’s website, and they claimed that it optically outperforms the Nikkor 17-55mm F/2.8 lens.  I can tell you that the images I shot with it are very sharp and have excellent color contrast.  It is a great normal lens for general use on a camera like the Nikon D5000, D90, or D300s.

With the Tamron 17-50mm F/2.8 VC, other photographers will wonder how you took such sharp images.  Pro quality images at a reasonable lens price! 

Keep on capturing time …
Darrell Young

Friday, July 1, 2011

Nikon D300s vs. Nikon D90 - Noise at 6400 ISO

I have been reading various opinions on the internet where people are claiming that the Nikon D90 has better looking images at high-ISO sensitivity settings than the Nikon D300s. It made me curious! So, being the extremely humble and modest fellow that I am, I thought I might offer my opinion. :-)

Since some may just be picking up cameras and firing—without thinking much about settings— and then making comparisons of their images on the LCD monitor, I tried to do the opposite. I sat down with my new D300s and my sweet wife's D90, and did a carefully controlled test of the two cameras at identical settings, and with the same AF-S Nikkor 16-85mm F3.5-5.6G VR lens.

Here is a direct "JPEG fine" comparison, with no retouching. Personally, I feel that the D300s image is superior by a slim margin. Make your own choice as to which performed better by examining the images for yourself:

Both images are:

  • 100% cutouts at about 840 pixels wide (see link for full size)
  • JPEG fine (camera processed)
  • 6400 ISO (Hi 1)
  • 1/60s @ F8
  • 85mm (AF-S Nikkor 16-85mm)
  • High ISO NR at NORM
  • NL Picture Control at default settings
  • Direct flash from the popup speedlight
  • Active D-Lighting LOW

Attached Image

Attached Image

Looking at both of the originals carefully I have determined that the Nikon D300s is sharper, has less noise, and slightly less contrast. The D90 has significantly more color noise. Both cameras performed in an amazing way at this high level of ISO sensitivity. The sharpness on both is excellent.

I feel that the D300s beat the D90 by a slim margin in overall noise, but by a larger margin in color noise. There is no way I can display the original image I see on my screen, even though I am saving this at Level 12 in Photoshop. The re-compressed image is much worse looking than the original, which teaches me that resaving a JPEG even once seriously lowers the quality of the image.

Both of these cameras performed at levels that surprised me. I normally never raise my camera's ISO sensitivity above 200, much less to 6400. However, I may just start venturing into higher ISO territory now. Technology seems to be catching up with our needs for excellent digital imagery.

Keep on capturing time ...
Darrell Young