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Sharpest Zeiss G2 Lens

G

Guest

I was speaking with a fellow G2 owner yesterday..he said he thought the 28mm lens is the sharpest of the G2 lenses. What's the opinion of the G2 group?

Jeff Roberts
Colorado USA
 
Based on resolution, my opinion (in descending order):

45, 28, 90, 21, 35. That said, even the 35 is "sharp."

I've not formed an opinion on where the 16 and zoom fit in. I'll note that resolution is but one of several important qualities a good lens must have.

--Rick
 
> [..I'm interested how you ran your resolution tests. And the distance at which you ran the tests. I have noticed each lens may not focus in the exact same point using AF technique...At one meter, they could be off an inch or so in either direction. ]
 
I have a resolution test chart that instructs setting the distance between the front lens element (not the film plane) and the chart by formula, based on the focal length. I use manual focus mode after converting the distance between chart and film plane to metric (another reason I need that metric tape measure!).

Frankly, it's a pain to do and the amount of the chart that appear in the resulting photos varies from lens to lens.

The results viewed through a good loupe are reasonably informative, but far more important than hard numbers from formal tests are images from the field. As an easier approach, you can probably learn all you need to know about a lens' resolution by shooting a brick wall from, say, ten meters using slow film and a rock-steady tripod. This will reduce the impact of certain lens chracteristics such as bokeh, color saturation, etc., as well as eliminate the effect of focus errors on the part of the body (except perhaps with the 90 wide open).

There are some good articles on lens performance on the Zeiss, Germany website.

--Rick
 
Jeff, the sharpest lense for me on the G2 is the 45. In fact this has produced me the sharpest pictures I have ever seen from 35mm lense. William.
 
> [..Rick,

Thanks for the description. If I may, I have some other questions. Did you do an exposure series? And which f/# did you find was best? Lastly what film was used?

Thanks. I just got done similar tests myself but less elaborate.

Dave ]
 
Hi Dave,

I'd better not make up detailed responses, it's been almost three years since I ran those tests and I suffer from CRS :)

What I will say is that there were no "A-ha!" moments wherein lens X magically and dramatically improved at a certain f-stop (I ran the tests in two-stop increments). Some have described the 35 as doing exactly this, however.

I've been meaning to do it all over again from scratch for my expanded lens collection, including the zoom. I also want to test the T3 against the 35 Planar and the zoom @ 35. Let's find out who's king of the hill!

I've not done an exposure series, but it's a good idea and probably would be more informative than a resolution test. The MacBeth Color Checker would be a useful tool for the task.

Either Kodachrome (25 or 64) or Velvia will be a good color film choice. If you can still get it, Kodak Technical Pan would be an excellent B&W choice.

--Rick
 
> Hi Rick,

Exposure is very important when doing resolution tests. If you want to do your tests again I would suggest the following:

1. Use B&W film such as Tech Pan. It is still made. This way you won't have to worry about which color film layer is resolving what. 2. Do an exposure series at each <font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">• will be a maximum for each <font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">• you can resolve every target your too close. 3. Try to illuminate each test the same to get the same image contrast. If you are shooting bar targets 1000:1 is a good ratio. 4. If you shoot more than one roll of film, process them all together using std contrast development.. 5. Read your images with a high power microscope. Have someone else read your images also. Average the two results

If you want help reading, send the images to me.

Dave
 
>Hi everyone, So far I have liked my pictures that I had taken using the 28 and the 45mm. I recently picked up a used 90mm and got my first roll of film back. Not many of the pictures I had taken were in focus? Is there some basic rules I need to follow in using the 90mm? Thanks.
 
Thanks Dave,

While it's beginning to creep into "reminds me of a job" territory, your technique sounds robust and probably a lot more reliable than mine, in terms of results. I'll have to see if I'm up to the task!

Can you please explain your point #2 a bit further for me? I'm not sure I'm following it (the web board is displaying two series of red dots w/in the text).

Thanks,

--Rick
 
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