Sharpest Zeiss G2 Lens

Guest · Jan 9, 2003

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

Guest · Jan 9, 2003

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

Guest · Jan 9, 2003

> [..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. ]

Guest · Jan 9, 2003

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

Guest · Jan 9, 2003

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.

Guest · Jan 9, 2003

> [..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 ]

Guest · Jan 9, 2003

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

Guest · Jan 9, 2003

> 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 Â•Â•Â•Â•Â•Â•Â•Â•Â•Â• will be a maximum for each Â•Â•Â•Â•Â•Â•Â• 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

Guest · Jan 9, 2003

>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.

Guest · Jan 10, 2003

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

Guest · Jan 10, 2003

Ming Ting,

Which G body are you using? The G2 autofocus system is apparently more accurate than the G1. Also, some cameras have software problems that interfere with proper focusing with the 90. Do some careful film plane to subject testing with a tape measure against the camera's digital readout to ensure it's focusing correctly. If not, you'll have to get the body serviced by Kyocera. (This is a well-documented problem.)

--Rick

Guest · Jan 10, 2003

> Rick is this your point of question?

2. Do an exposure series at each Â•Â•Â•Â•Â•Â•Â•Â•Â•Â• will be a maximum for each Â•Â•Â•Â•Â•Â•Â• you can resolve every target your too close. ----------- Best if you could do an exposure series with the f/# unchanged. Ideally the light source should be modified to keep the shutter speed constant and vibration in the camera the same. But you are right, doing it that way begins to sound like work. So I suggest you use your shutter and do plus / minus 3 stops in half stop increments. After processing you will see resolution increase to a maximum then decrease. Like a unside down parabola. Don't know if the peak will be at correct exposure or a little over or a little under. Depends on a lot of things. Depth of field will be greatest at f/16 but maximum sharpness should be with f/8. But I am guessing f/8 w/o data. So with each f/# there will ba a maximum but the width of parabola will be different.

"If you can resolve every target you're too close" means you need to push the test beyond what the system can resolve. There must be some targets you can't read. They are too small. If you can read them all move the target away ...make them smaller.

Hope that helps.

Dave

Guest · Jan 10, 2003

Thanks Dave!

--Rick

Guest · Jan 25, 2003

I own a G2 and all of the lenses except the 16mm and the 35-70mm zoom. All of them are exceptional, but I have always felt that the 28mm is the best. Images that I get from it seem to be crisper than those from any of the others. Oddly, it is the lens that I use the least, simply because the 28mm focal length is too wide for general use, IMO.

I have used the 35mm extensively. For awhile, I was bothered by the bokeh at f2-2.8, but no longer. It beats just about any other 35mm on the planet.

Guest · Mar 22, 2003

I myself have noticed taht my G2, 45mm lens and Kodak T400CN make a very sharp combination.

Guest · Mar 24, 2003

I have G1 not G2 with CZ 45mm. I got remarkably sharp result using T400CN, and I am now trying Ilford HP5+ and Delta. I've tried also colour slides (Kodachrome), the sharpness and colour are extremely beautiful for available light photography.

Trisnadi

Guest · Mar 26, 2003

I have all the G lens except the zoom. 45mm is the sharpest. 20mm is the best of its class. 28/90mm is the third place of this competition. When you are talking 16mm, it is a good lens with minimal distortion. However, the resolution is not the best among the other G lenses.

Leo

Sharpest Zeiss G2 Lens

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