Surprising Close-Up Lens Results

CU Tests-01How well do lenses really work up close when you use extension tubes or an achromatic close-up lens? I have always had good results with them, but recently I decided to do some tests to see what I needed as I expand my GH3 system (my budget is not unlimited!). In working with Art Wolfe on a book about composition (that will be out this fall), Art shared that he never travels anymore with a macro lens. He just uses extension tubes.

One reason I wanted to do a test was because of my Tamron 90mm macro that I really liked with the Sony gear I had been using. I got an adapter for it to use with Micro Four Thirds (GH3 format), but it did not have any automation. The internal aperture does not work. The adapter has this interesting work-around -- it has its own built-in aperture. The problem with that is that it cannot have actual settings on it (since it could be used with different focal lengths), and it is obviously not designed into the camera, i.e., some sharpness is likely to be lost. But how much?

So I decided to test it. I also decided to test and compare my 12-35mm f/2.8 lens with extension tubes and achromatic close-up lens (a Century Optics +7 optic). Unfortunately, I no longer have any Sony NEX cameras so I could not compare the macro at its best with the use of the adapter.

The results were really fascinating. The photo at the top of this blog is a shot of a piece of petrified wood. I have never been fond of test charts. My friend Chris Robinson (editor of Outdoor Photographer) says that we don't photograph test charts in real life, so they don't tell us everything. When I do a test, I like to photograph something real. You then see how the lens handles things like tonality, depth, gradations, as well as sharpness, in a real-life situation. Hence the petrified wood.

The macro results were not as good as I had hoped, though they were not bad. That is a challenge with this adapter. It just is not allowing the macro to be at its best. However, I was blown away by the results from the 12-35mm lens with extension tubes and achromatic close-up lens. The following cropped details from the larger shot of the whole piece of petrified wood give an idea of what I saw. These are all from the center area of the photo.

These shots are all mid-aperture range (not sure what that would actually be for the macro, but these are at f/8 for the other shots) which is where I expected to see maximum sharpness. None of the shots have been sharpened. I shot the 12-35mm at 35mm because short working distances make other focal lengths less likely to be used and extension tubes are problematic. Everything was locked down on a solid tripod and focusing was done with a magnified view on the LCD.

Macro:

CU Tests Macro-01

12-35mm at 35mm with extension tubes:

CU Tests Ext Tube-01

12-35mm at 35mm with achromatic close-up lens.

The results with the 12-35mm with both extension tubes and achromatic close-up lens were both remarkable and surprising. You really never can predict this, but I did not expect these results. They are really good. This lens with both extension tubes and an achromatic close-up lens does really, really well, as well as most macro lenses. Since the original lens was never designed to be used with either extension tubes or an achromatic close-up lens, you never know how good it was.

I had hoped that the macro lens would do better with the adapter than it did. Not being able to use the aperture of the lens as it was designed is a problem.

That said, what is the difference then between the 12-35mm and a macro lens. Wide-open, it is not as sharp -- I would expect the macro to hold sharpness well from the widest to smaller f-stops (not smallest -- I'll get to that in a moment). In addition, at wider apertures, the edge sharpness is definitely not as good as center sharpness (though in a lot of nature photography, that really doesn't matter).

Since I was checking, I decided to check the whole range of f-stops (I did this, sort of, for the macro, but that really isn't a good test since I could not use its "real" f-stops). As expected, sharpness peaks in the mid-range (f/5.6-8 is outstanding, f/11 is excellent, though a little less) and drops off at smaller f-stops (f/16 gets worse and f/22 gets bad).

That problem of f/22 is so very common yet I find most photographers don't realize that they are often losing sharpness when they stop the lens down below f/16. This is due to something called diffraction. The f-stop gets small enough that it starts to affect how the light goes through the lens. This diffraction effect can significantly reduce sharpness. It is rare to find a lens as sharp at f/22 as at wider apertures (and smaller apertures can be awful), and often I have found that there is a very distinct drop in sharpness from f/16 to f/22. Check these results:

f/8

CU Tests f-8 -01f/16

CU Tests f-16 -01

f/22

CU Tests f-22 -01A quick note. My video course on photographing the intimate landscape is now available on Craftsy.com. You can get 25% off the cost of the course by going here.

 

 

About Rob Sheppard

I am proud of the work I have done as a photographer, author, naturalist and nature photographer, editor and videographer. I love the natural world, and that can be a native bee in my native plants garden as much as a visit to a national park. I am a husband of a beautiful and smart wife, a father to my outstanding son and daughter, and one who lived in Minnesota most of my life, but now loves the variety and very long growing season of Southern California. I have written and photographed a lot of books and magazine articles but what is most important to me about them is knowing that I have helped people become better photographers and gain a better connection to nature. I work to help people connect with photography and nature through speaking and as a workshop leader, too. All of this has gained me a Fellow award with the North American Nature Photography Association. Many people knew me as the long-time editor of Outdoor Photographer magazine and I am still connected with them as a contributing editor. A short list of some of the books I have done: Landscape Photography: From Snapshot to Great Shot, Magic of Digital Landscape Photography, The Magic of Digital Nature Photography, National Geographic Field Guide to Digital Photography, The Power of Black-and-White in Nature Photography and Reports from the Field (an iBook). My website is at www.robsheppardphoto.com; my blogs are at www.natureandphotography.com and www.mirrorlessnature.com.
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10 Responses to Surprising Close-Up Lens Results

  1. Steve says:

    Been using extension tubes and Nikon close up filters for decades with an SLR. The photos have been sold, published, put on websites and enlarged which tells me they are sharp. I learned years ago from John Shaw that these 62 mm thread filters can be used with a step down ring on a telephoto even though the lens had a 77 mm thread for filters with no problem. Nice review of diffraction, easy to forget when you're trying to get more DOF.

  2. Jeff Engel says:

    For many years I used the Nikon acromatic close up lenses, until finally springing for the 105macro. I find the macro lens sharper, but the close up lenses were quite good, and far easier to use. Putting them on a telephoto zoom lens was wonderful: to change image magnification you merely zoom in or out. Don't have to move the tripod. That single advantage might outweigh the slight increase in sharpness (and considerable increase in weight) of the true macro lens.

  3. Hugh Nourse says:

    Long ago I remember a column of George Lepp's answering someone who was saying that his macro shots were not as good as he would like with the Canon or Nikon two element macro filters. George's response was that even though John Shaw advocated their use, John used a macro when he really needed a sharp macro photo, as did he, George, at that time. It is very interesting about the spacers because they allow the use of zooms or different lenses than the ones made for macro use. Perhaps this is another myth built up over the years that is no longer true.

  4. Rich Bahl says:

    Rob - I am looking forward to your book with Art Wolfe!

    More to the subject I purchased a Canon Achromatic lens per your macro photography book. I experimented with it briefly and it seemed OK. I haven't tried it on the 35-100mm Panasonic lens yet. Have you performed any tests with that lens yet? Also where do you find the Century Optics close up lenses? The web site doesn't seem to have them. They should be good since they are a part of Schneider optics.

    Rich

  5. Rich Bahl says:

    Thank you Rob - I went through all the pull down menus at the Century/Schneider web site and didn't see them. It never occurred to me to do a search on the site. I knew they would be pricey with the Schneider name on them but the $270 price tag did surprise me.

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