Apparent Sharpness of 210mm Sironar N

[William D. Lester]

I commonly use a 150mm f5.6 Rodenstock Sironar N lens on my Technika V and I find it provides very high sharpness / acutance? Not long ago, I purchased a used 210mm f5.6 Sironar N which appears cosmetically flawless. I have not conducted any meaningful tests or side by side comparisons yet, but it seems that when I look at negatives made with this lens that they lack the apparent sharpness of the 150mm. Should I expect a 210mm to look as sharp as a 150mm? Is a Rodenstock 210mm f5.6 considered to be a good performer or is there a 'preferred' lens of this focal length?

[Ernest Purdum]

There certainly is no reason that you should be able to see any difference by looking at the negatives. The whole Sironar N line has an excellent reputation. Something is wrong, perhaps not necessarily with the lens itself. Try to think about any other factor which could be influencing the results.

[Gem Singer]

Hi William,

I do not own either of those lenses. But, if I did, I certainly would expect my Rodenstock 210 f5.6 Sironar N to be every bit as sharp as my Rodenstock 150 f5.6 Sironar N.

Both are very acceptable lenses, with good reputations. Of course there are the newer Apo models of the Sironars out there, as well as several other fine 210 lenses made by other manufacturers. However, it would take very extensive testing to determine which one is the sharpest, or, as you call it, the "preferred" lens.

Since you are able to detect a lack of sharpness just by looking at the negatives, you either have a defective lens, or, you are using a cammed rangefinder for focusing, and the rangefinder is not accurate.

Do some careful focusing tests, using a solid tripod. You should be able to pin point the problem.

[Jorge Gasteazoro]

I have a 300 Sironar N and it is very, very sharp. If you dont see the same sharpness with your 210 as with your 150, there must be something wrong.

[Leonard Evens]

I agree with the others. One random thought. For a subject at the same distance, you do get less depth of field with a 210 mm lens than you would with a 150 mm lens. It is remotely possible that you are interpreting that as a lack of sharpness. Also it may be that you have to adjust your focusing technique for the longer lens. The only way to be sure about any of this is to do some careful testing of the lens under controlled conditions. The first thing to try is to take a picture of a detailed flat surface, such as a newspaper taped to a wall. You have to make sure the standards are perfectly parallel and also parallel to the subject plane, and you have to focus very carefully. Do that with both lenses but at different distances from the subject so the images are roughly the same size. If there is anything seriously wrong with the lens, you should see an obvious difference in the two negatives.

In the past I've been misled about lens quality when trying out a new lens because I didn't take into account the fact that things work a bit differently for different focal lengths, but careful testing showed me the source of my problems, which was my technique, and not the lens.

[Jim Rice]

My 210 Sironar N is very sharp. It is my most used lens.

[Steve Clark]

Hi William I had the same 210 for a while and found it to be a good lens, but not a great lens. As I had other lenses that were much more pleasing, it was sent on it`s way with no regrets. It was replaced with a 180 Nikon that I am quite happy with...

[Dan_1982]

I don't have the web site url, but I think it is done by Chrisopher Perez - lens tests. When I was in the market awhile ago for a 210 I checked the tests, and the 210 Sironar N (and maybe even the S) didn't seem to do as well as the Schneider Apo Symmar. Schneider now has an improved version - the "L" version.

However even within the same model there are variations from sample to sample. I once had a Nikkor 210mm and I was not pleased with it's sharpness at anything other than close to infinity. I never tried a Rodenstock nor a Schneider. However as one other person said, depth of field could come into play in comparison to a 150. Also the longer a focal length is, the more correction is needed, generally - ie. it's easier, cheaper to make a sharp 150mm than a 210mm, and easier to make a sharp 210mm than a 300m etc. (esp. chromatic abberations). If you are really picky about getting the best results from table top to infinity, I would look into the Schneider Apo Symmar (or the newest version).

[Lloyd Lim]

I have a Caltar-IIN 240/5.6 which is the Sironar-N and when I first got it, it seemed to be very unsharp compared to another 135/5.6 Sironar-N.

It was only later that I found out that I did not screw the back element in correctly, and hence the element spacing was incorrect. Once I corrected that, the Caltar IIN 240/5.6 has become a very sharp lens!

Try checking on your lens mounting. It might be a "leetel" bit off

[Øyvind Dahle]

Eugene Singer wrote: "Of course there are the newer Apo models of the Sironars out there"

I believe Apo-Sironar and Sironar to be the same lens, so they found the formulae to be good enough to put the "apo"-name on it, so your lens should be a good type. The latest is a Apo-Sironar-N, wich is a different design.

Øyvind