How do I get the best sharpness from a Zeiss Jena Pancolar MC lens?

Question

I've just ordered a Zeiss Jena Pancolar MC 50mm prime lens, and have been reading up as much as I can about how to get the best quality images from it.

It's my intention to use it mainly with 3 different film SLRs, but occasionally with an APS/C Samsung mirrorless.

As I understand it, the sharpness on this lens is most crisp in the centre of the frame (as with my other 50mm lenses really), but I can't find much information on the way the lens behaves at different f-stops with regard to sharpness around the edges of the frame.

I realise that it is very subjective to ask how to get high quality images, but I'm curious if anybody with experience of these lenses has any tips on how to ensure as sharp an image as possible.

Mostly, I tend to photograph scenes of industrial decay, landscapes, and various wild plants and flowers in reasonably bright sunlight, however as the uk weather tends toward dim days for a lot of the year, I find that I'm often taking shots in much lower light than I'd like.

When I'm photographing plants, I tend to place the subject close to dead centre so this isn't too much of a worry for me, but when I'm photographing buildings or industrial scenes, I like to get as much of the edge of the frame in sharp focus as possible. One a session in Wales, it was fairly dark so I had the lens wide open (in this case, it was a Fujinon 55mm) and found that there was noticeable loss of sharpness at the edges of the shot. Stopping down a little and shooting for longer resolved this nicely.

I'd be grateful for any tips from anyone who has used one of these lenses in the past. I'm flying a little blind as on paper it seems like a superb lens, but I don't know anybody personally who has used one to consult.

Answer 1

As a rule-of-thumb, the sweet spot for maximum sharpness is about 2 f-stops stopped down from the lens's maximum. At wide-open, a lens is usually slightly degraded because the peripheral figure (shape of the curve) is quite steep -- thus image-forming rays originating there are more likely to go astray. As you stop down, the figure is more gentle. However, as you stop down, the twin plagues of diffraction and interference begin to take a toll on acuity.

Answer 2

In addition to Alan's info, this site did a review and compiled an MTF chart for the lens, which you may find of interest. In your lenses case, the sharpest test seems to be at f/5.6, or 3 stops down from wide open.

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On lens sharpness as a whole...You can compare MTF charts to get an idea of relative sharpness comparisons between lenses. Some examples:

Canon 70-200 f/2.8 II:

And this is the 85 f/1.2 II:

You'll notice that at every measure, the 70-200 is sharper, or at least, produces more line pairs. As it should, it's one of the sharpest lenses ever made.

However, the 85 is the prized bokeh king in the Canon lineup.

So the question is, is sharpness everything? And now, the subjective argument can commence.

I think the important thing to note is that you should learn your gear, where it excels, where it falls short, and shoot accordingly. That 85, for example, doesn't resolve all that well at f/1.2 - but that's precisely the aperture that people buy it for.

Answer 3

The achilles heel of decades old lenses, compared to current ones, is often in the coatings - you might need to be more careful with situations that can cause flare, both of the "ghost creating" type and the "global contrast reducing" type. Lenses made for film usage sometimes have much less attention paid to dealing with light reflected back into the rear element (as from a sensor)...

Use lens hoods where they do help; if adapted to APS-C digital bodies using a tighter (narrower/longer) lens hood might be advisable, just not so tight that you actually create an external aperture (occasionally, advice suggesting lens hoods that have a smaller opening than the front element diameter can be found. Often describing improvements in IQ similar to stopping down the lens. Guess what....). Mind that lens hoods help nothing if the flare source is right in the frame...

In case corner sharpness is unsatisfactory at the apertures you prefer to use, consider going for a composition that does not put in-focus things in the corners - or if most of the subject is in focus all across the frame, try to take advantage of the corner softness/lower corner contrast to highlight your center subject.