April 28, 2008

Leica 40mm Summicron-C vs. CV 40mm Nokton

So, I was getting bored working at home but didn't have the time to go out to do any meaningful photography. So I decided to do the next best thing - some meaningless photography! a.k.a. lens tests. Since I had newly acquired a Leitz 40mm f2 Summicron-C, I decided to find out how my usual street lens, a Cosina-Voigtlander 40mm f1.4 Nokton MC, matched up against it. So I drew up a plan and shot off a roll of film and here are my findings.

I tested for the factors that I find important in how I use these lenses - i.e. handheld street photography. Of course, all the standard caveats of informal testing of photographic equipment apply - sample variation, non-objective criteria, do-your-own-testing yada yada - but I hope you still find the review interesting.

Camera was a Bessa-T, with TMax 100 film at EI 64 developed for 6.5 mins in HC110B (.1 - 1.35 density range). Everything scanned with a Nikon Coolscan IV at 2900 dpi. Minimal or no postprocessing applied. Where I have applied even the slightest curve etc, exactly the same processing has been applied to all the shots in a particular test (with recorded actions in PS). Both lenses were used without any hoods or filters. In paired shots, the Summicron is first (left or top) followed by the Nokton. Excuse the water stains - I ran out of photoflo! Remember to click on the photos to see them at full size.

A word on build. Both lenses look very well made - metal construction and smooth focus etc - although the Summicron-C would come out slightly ahead in build quality. Not that much of a concern for me, though. The Summicron-C is surprisingly compact but the Nokton isn't much larger - it sticks out perhaps 3-5mm more from the body than the Leica. The Nokton takes 43mm filters while the Summicron-C takes the ridiculous and difficult to find series 5.5 filters.

So, sharpness is up first. I mainly use a 40mm-ish lens on the street at medium to long distances and for some not too tight portraits, so those are the average distances I tested for. Here's the full frame test shot I used for average street distances, showing the areas I used for center and corner sharpness comparisons:Center sharpness first. The Nokton at f1.4 looks quite soft, but hey, it's 1.4!
Let's put them head on at f2. The Summicron-C is very slightly sharper an contrastier:
F4 and the difference is still prominent:And at f8, leading me to conclude that the Leica is very slightly but perceptably sharper in the center at relatively far distances:How about corner sharpness? Here's the Nokton at f1.4. Not pin sharp but looks pretty darn good for a corner at f1.4, IMO!:At f2 it's neck and neck, but the Nokton might just have its nose in front:By f4 the difference is quite clear and the Nokton is noticeably better than the Summicron-C:But at f8 the Summicron seems to edge ahead. But both lenses turned in performances in the corner above my expectations - overall I felt the Nokton was better:For near distances, I used this shot to test for sharpness - shows 100% center and corner crops:The Nokton at f1.4 at the center, again quite soft but acceptable at f1.4:At f2 the Summicron-C is sharp enough, but the Nokton disappoints:By f4 the Summicron-C is very sharp indeed while the Nokton lags far behind:At f8, the Nokton closes the gap a little bit, and about time, too. Overall, the Summicron appears quite a bit better for portrait distances:So with bated breath, I move on to the corner. A look at the Nokton at f1.4:Both are so-so at f2:Very hard to tell at f4 as well:By f8, I am slightly mad at both lenses but it looks like the Nokton might just be doing a little better. But overall, it's the Summicron-C that is sharper at closer distances, mainly because of its superior center performance over the Nokton:Okay, now let's move beyond sharpness to the religious debates on fuzzines, out of focus rendition, bokeh, what you will. It remains an important element of my photography, so let's test for it. I chose two kinds of situations - one with a busy and difficult background in the daytime and another with the kind of specular highlights one encounters so often, shooting on the streets at night. The first lot only show the top 2/3rd or so of the frame where the OOF action is. At f1.4, only the Nokton showed up with an entry. The famed hard edged bokeh that the Nokton has taken much stick for - people read about it and run away from this lens. I have always insisted that it has 'character' rather than just harshness, and I stand by that. The bokeh isn't creamy smooth, but it isn't really harsh. In fact, this kind of bokeh might work very well in gritty street shooting:F2 springs a surprise as the Nokton bokeh is much better than the Summicron-C which disappoints quite a bit with downright harsh out-of-focus renditions:Closer at f4, but I still think the Nokton is noticeably better than the Summicron-C. BTW, the Summicron-C continues to be contrastier in these shots and I think the Nokton shows a hint of veiling glare from shooting into the light - but nothing major at all, barely noticeable and then if you are looking hard:Okay, how about specular OOF highlights at night. These are quite important to me. I tested with both the lenses focused at 1m. Plenty of hard edges/character from the Nokton at 1m and f1.4 and even some of the more problematic flare. But it is the only lens that showed up, and when you need f1.4 at night, you need f1.4. I do think that if one is aware of how this lens renders highlights wide open, it can be used to great effect as an element in the photograph:At f2, both have more or less hard edges, but the Nokton looks much better to my eyes than the Summicron-C:Finally, I put them through a stress-test for flare. This is my desk with the table lamp turned up, shining into the lens (remember, no shades or filters) and both are surprisingly good at f2, although the Summicron is starting to show signs of flare at both the top right and bottom left corners. As before the Nokton shows just a hint of veiling glare but none of the problematic specular flaring that is so difficult to handle. In fact, the veiling glare seems to lower the contrast a tad bit in such very contrasty scenes:The Summicron-C turns out to be slightly sharper but the Nokton turned in better performances in the corners. The Nokton also has better bokeh all around and is more resistant to flare. But most importantly the Nokton is a stop faster and that seals it for me. I felt the Summicron-C's slightly better build and sharpness weren't enough to sacrifice the advantages of an f1.4 lens. So, there you have it. The best part of a day wasted and I am still keeping the Nokton!

12 comments:

Tristan said...

Thank you for this test - most illuminating. I was considering getting the Summicron-C even though I already have the Nokton (though the SC version). Now I think I shall not succumb to the dreaded GAS.

Anonymous said...

Hello, thanks for this comparison. But I have the impression that there might be a little mistake. In the "corner sharpness" comparison (brick wall) at f4 and f8 the left of the photos always look sharper. You say on the left side should be the Summicron, so there I am a bit confused.
regards
Matus

AB said...

Thanks for your comment. I do say that at f8, the summicron looks better. At f4 the results are very close. The Nokton seems very slightly ahead to my eye, but you might be right that the Summicron is a bit sharper there. In any case, I'd say they are very close in performance at f4. Glad you found this informal review useful, though.

Anonymous said...

Good test and it shows that the performance between the various lenses is really pretty close. I have had the Summicron 40 in multiples over the years and though nice, I prefer the Nokton 40f1.4's. The extra stop and the slightly tighter framing on a M2 (lenses filed down to kick in 35 frames). It becomes a good one lens/one camera kit for walking around. It can be used as a50 by just leaning in somewhat and as a 35 by taking a step back.

epand56 said...

What about the focus shift?
I have a Nokton 40/1,4 and it is very prone to focus shift. How does behave the 40 cron?

Peter said...

Thanks for this -- it's the test I've been looking for!

-Peter

http://hookstrapped.viewbook.com/

Anonymous said...

hi!very interesting.
I have a question. I should modify the summicron to reveal the 35mm frame on a leica m4p, is it true?
is the same with the nokton?
thank you very much

DM said...

Yes. I had mine converted and found the 35mm framelines a much better fit than the 50.

Anonymous said...

thaNk you very much man!

r4 dsi said...

Great post. Nice comparison between two lenses. Its very interesting.

Olivier said...

Hi. thanks for this very good test. In absolute terms, it would be hard for any lens to reach the level of the summicron's of this era. They are famous for having the highest centre performance (at the expense of a lower corner performance, as MTF graphs show). It is a very good performance from the nokton, albeit decades later, it really questions why one would buy a vintage leica over a modern and excellent cosina lens.

Anonymous said...

Great test. I own the Summicron-C and bought the Nokton today, because I do a lot of low light photography, and the Summicron always left me that decisive f-stop behind. So I trade off a little bit of center sharpness for 1 full f-stop - easy decision ...