Tuesday, October 4, 2011

Photo Tips: Ants in my Viewfinder

Lens Review:
AF-S NIKKOR 28-300mm f/3.5-5.6G ED VR (FX) Lens

In less than a week, my friend Lynda and I are embarking on our next trip.  We have traveled and photographed polar bears in Northern Canada, went on safari in Kenya and have marveled at cheetahs running from 0 to 60 miles an hours in several seconds.  In our upcoming trip, we are focusing on cultural photography in India, Bhutan and Thailand.  The age-old question is of course what photo equipment to take specifically when being on the road and in a different hotel every night – being prepared for every situation and yet not to be over burdened by a heavy pack, tripod and all.  On top, for our 6+ week travel we each contemplated the necessity of taking 2 bodies, one with a DX and the other FX sensor format.  Lynda had been photographing with the Nikkor 18-200mm Dx lens, a very nice overall range and a preferred lens for many travel photographers.  However, after using more serious top-end pro-lenses like the 70-200mm lens recently, this all around lens while giving nice images tends by comparison to be a bit soft.

Then earlier this year, Nikon came out with the new AF-S NIKKOR 28-300mm f/3.5-5.6G ED VR lens.  So before the impending trip, Lynda took stock of her lenses and decided to buy this new lens and ‘test drive’ extensively and compare it to four other lenses (see list below).  Having been an analytical research scientist all her life, she put her scientific hat on and developed a testing matrix taking every thinkable variable into account and then meticulously tested and compared results under the proverbial microscope.

Having seen the results, I wanted to share her assessment of several lenses specifically with respect to sharpness and thus, invited her to write a guest lens review for my Travel TidBits blog and today, here it is!

I won’t steal the thunder and won’t reveal her overall results.  It was an interesting experiment and I want to applaud her for her thoroughness.  So please read on….

   Lens Review by Lynda Sanders

Well, in preparing for an extended trip to lands afar (India, Bhutan and Thailand) I wanted to review and update my equipment with an eye to size, weight and image quality.  And versatility - why take two lenses if one will do, since we will be doing some serious hiking, and my feet get sore these days.

Some years ago I purchased my Nikon D300 body (before even the D300S was available) with, as was quoted to me at the time 'the only lens I would ever need', the AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VRI took that equipment to Myanmar (Burma) and shot exclusively with it, and was thrilled with the results. (http://www.pbase.com/lyndasanders/burma).  I thought I was set for life.

Then, more recently, I went to a butterfly exhibit in the San Diego Wild Animal Park (highly recommended, once a year in April) and armed with a Tamron 1.4x converter, got some shots that still needed serious cropping, such as a butterfly's soccer ball-design compound eye.  When I compared my images with those of companions who had different lenses, I developed a suspicion that my beloved 18-200mm was not as sharp at the extremes as it might be when challenged with a tough situation.

I have since moved on and upward, and acquired a D700 body (full frame sensor vs the 2/3 sensor of the D300) and other lenses.  Life was good.  Then, the AF-S NIKKOR 28-300mm f/3.5-5.6G ED VR (FX) lens was released.  This of course gives almost exactly the same range as the 18 -200 on the smaller DX sensor.  With a big trip ahead, the question was, should I get this 28-300mm lens for my D700?  Is it just a bigger, heavier version of the 18-200mm but marketed to the FX people?  It has a great range, but, key point, it does not have a constant aperture over its zoom range, putting it in a 'less than fantastic' category.  What to do?

For me, there was only one option - buy one and test it against other lenses, owned and borrowed, and see how it looked.

These are the Nikkor lenses tested on the Nikon D300 or D700 body:

  • AF-S NIKKOR 28-300mm f/3.5-5.6G ED VR (FX)
  • AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR (DX)
  • AF-S NIKKOR 70-200mm f/2.8G ED VR II (FX)
  • AF-S NIKKOR 24-120mm f/4G ED VR (FX).

As a scientist (in a previous life), and for those of you to whom this is meaningful, I designed an experimental matrix, changing only one variable at a time.  I used a few different lenses for comparison, including the amazing AF-S NIKKOR 70-200mm f/2.8G ED VR II (FX) which is my current favorite lens.

Experimental Matrix for Testing and comparison of Lenses
Camera body
Focal Length (used)
35mm Equivalent

ISO kept constant at 500, aperture priority at f 6.3
My test real-life object was a marching ant as seen in the banner at the top of this blog, and  focused right on the center of the ring of the eye facing you.

And - the results:

Sharpness of the 18-200mm vs the 28-300mm on the D300 body:

The eyes have it.
On the D300 (with a small size sensor) there is no doubt, the 28-300mm gives a sharper image than the 18-200mm.  Look at that eye-ring.  And the forked nose, even though it is probably just in front of the plane of focus.

How does this compare with a really great FX lens on the D700 body?

Not so much of a difference.  Bear in mind, this is a small crop of the originals to highlight differences.  The 70-200mm is a high-end lens, and the 28-300 gives it a good run for its money.  We begin to see pixelation before we see differences in sharpness, and that is as good as it gets.

And, what do we think of the 24-120mm lens by comparison?  This is a constant aperture F 4.0 mid-range, gorgeous zoom.  For someone wanting 'good glass' and not satisfied in principle with a variable-aperture zoom, this might be an alternative to the 28-300 for a general-purpose lens, but of course with a more limited range.  (Life is a series of trade-offs, have you noticed?)

Wow.  The 28-300mm stacks up pretty well against this lens too.  A small qualifier:  to maintain constant parameters, both shots were taken at 120mm, which is in the middle of the range (optimum for sharpness) for the 28-300mm but at the extreme of the range of the 24-120mm.  So maybe the comparison is not completely fair.  But, the 28-300mm still looks pretty darn good.

Another technical qualifier:  All lenses have specs (specifications) of a given range.  This means that each individual lens performs somewhere within this acceptable range, but lens-to-lens there will inevitably be small variations.  So, I can really only say that the particular lens I have performs as shown.  But, I would expect that other 28-300mm lenses would be closely similar.

Footnote:  I noticed that the focusing of the 28-300mm was just a tad slower and noisier than the 70-200mm (my reference for a really nice lens) and if you read other reviews, I can understand why some consider it not the best for wildlife photography, where you need the fastest focusing possible to track that bald eagle zipping by overhead.  But it's a lot better than other lenses I have tried (like the astoundingly slow-focusing older 80-400mm lens) and I'd judge it fine for all but a running cheetah.

So, at the end of my study of the ants, I am going to keep this 28-300mm lens and plan to use it as my workhorse lens for my upcoming trip.  I'll take some other lenses, like the 16-35mm F 4.0 and 50mm F 1.4  for when I'm seriously worried about sharpness.  And maybe I'll take an extender or two for further flexibility without much weight - there are pros and cons there, but I leave that discussion for another day.

Happy shooting!
Lynda Sanders

So, here you have it. 

Thank you, Lynda, for your thorough ‘test drive’ and for sharing your comparisons and results.  Since we will travel together, I am sure we will have lots of other discussions on equipment and compare Lynda’s ‘workhorse’, the 28-300mm lens, with my favorite, the 24-120mm lens, in our daily evening download and review.  I am sure in the end we will both bring back lots of great images and not to forget:


So, watch my Travel TidBits from the road through India and Bhutan!

Til next time,