Since the question of “Which wideangle for my M?” had come up several times in our forum, and since there did not seem to be any clear-cut answers, I decided to compare these three lenses for myself. I have read and re-read Erwin’s reviews of the 21’s and the 24, but had difficulty integrating his results. In my mind, his review makes any 21 prior the to Asph version seem like it is not worth having – they didn’t bear the Leica badge with full honor. He boasts on the performance of the 24A, but makes no comparison between it and the 21A. The problem for me was that my 21 Pre-asph seemed like a pretty decent performer. Not as sharp as my 24, but certainly not horrible, and notably better than any of my Nikon 20mm counterparts. In actual use however, I found myself continually choosing the 24 over the 21 to go into my bag because of its superior performance, yet I found myself more than once wishing I had brought the 21 for that little bit extra spread. So, curiosity got the better of me. Could the 21 Asph be as good as the 24? It was difficult to imagine it could, as the 24 is such a stellar performer, but I wanted to know the answer for myself. Here is what I found out for those of you interested – But please note that I offer this with all of the usual disclaimers about my tests not being the end-all for everybody else, my giving subjective comments about objective results, non-perfect scientific testing criteria, etc:

First, a small note on ergonomics: The 21P has a quicker focus throw of about 90* from .7M to infinity, and has a slightly larger aperture ring than the 21A. The 21A matches the 24 in a longer focus throw of about 105*, and both the 21A and the 24 have similar aperture rings that are smaller than the 21P.

Test-target results:

F2.8: Here I got a surprise. When comparing the centers for the 21A and 21P, I found the 21P to be sharper(!) Not by much, but definitely a visible difference. I double-checked my notes to insure that I had not inadvertently swapped the slides. Indeed, I hadn’t. At the corner I received another surprise. The 21P is notably better than the 21A(!!). The 24 is the overall winner at f2.8, being sharper in the center, yet it essentially only equaling the 21P at the corner. It is worth noting that the 21P is performing significantly better at the corner than at its center. Perhaps an issue with under-corrected spherical aberrations or even a curvature-plus-focus issue? Yes, I was beginning to regret my 21A purchase as it looked like the 21P wasn’t all that bad… as I had originally thought.

F4: An interesting phenomenon here. The 21A takes a quantum leap in image quality at the center, now almost equaling the 24, which also takes a fairly significant jump in quality. Both are clearly better than the 21P in the center whose performance here is actually a bit lower than it was at f2.8. At the corner, the 21A improves a lot, but the 21P also improves a little, and in fact just edges out the 21A here; and even very slightly edges out the 24(!) So, the 21P loses the center, but hangs on to the corner by a tiny margin.

F5.6: Here the lenses all come into their own and behave much as we might expect. The 21A is very sharp in the center, but not quite up to the 24. The 21P lags behind notably. In the corners, the 21A is now notably better than the 21P, and for all intents and purposes the 24 and the 21A are equal here. The 21P is still performing better in the corner than the center, but not by much, and is showing essentially even results across the image.

F8: The results are essentially the same as above, with the 21A losing a little bit more ground to the 24 in the center and the corners.

F11 and 16: The 21A and 24 fall off here, but interestingly the 21P actually improves to the point where it is almost as good as the other lenses. So, for all intents and purposes in general picture taking situations, one can consider all three lenses to be equal performers at these stops.

For the field test, I shot the same image with each lens, keeping the exposure and focus-point identical for each lens. All shots were hand-held. For some of the shots I also altered my shooting position with the 24 relative to the 21 in an effort keep the main subject of uniform size for comparisons in the final image.

Field test results and my “IMO” Conclusions: Do I get (or in my case keep) the 21A or 21P? Based on the test-targets, if I was looking to have the sharpest image possible with a 21, and cost was no object, the 21A would be the answer. However in actual shooting situations, these differences became very slight, and almost unnoticeable in many images. In the sweet-spot stops – f4, f5.6, and f8 – the 21A is clearly superior to the 21P on the test-targets. In the field these differences are mitigated to a significant degree, and while the differences are still noticeable, I’m having a tough time convincing myself they are significant enough to justify the extra cost of the 21A. Furthermore, if you generally use your non-aspheric 21 at f11 or f16 for maximum DOF in the typical sweeping WA shot, there is probably no reason to upgrade to the 21A, as I doubt you will notice any differences at all. In a few of the field tests images I did detect some crispness in the 21A and 24 images that wasn’t present in the 21P images, but to be truthful it was a slight difference and probably wouldn’t bother me in most cases. So, I would not recommend one upgrade to the 21A unless they actually see softness in their images that bothers them. While the E55 filter size on the 21A presents another plus for me, as I don’t have to carry any E60 filters for the 21P and have other E55 lenses, it is certainly not a compelling enough reason alone to justify the additional cost of the 21A. As for size/weight, all three lenses are essentially the same profile so the differences in my mind are not significant either. While the 21A is a superior performer to the 21P, I have to be truthful and regretfully admit that I feel I’ve wasted my money on its purchase for the limited gain I am detecting. :-(

Between the 24 and 21A, I’d have to say we are comparing an f2.8 lens in the 24 to an f4 lens in the 21A, which could become an issue while shooting in low light or building interiors – however hand-held shots at slow speeds probably have bigger limitations than the difference in optical performance here. In the field tests, most of the shots between these two lenses appeared almost identical in resolution, with the occasional edge given to the 24. Based on the test-target results, if you need the sharpest super-wide period, the 24 is the superior performer. However, from f4 on these two lenses are pretty darn close – close enough that most of the differences will not be noticed when using these lenses hand-held, so perspective will probably become the dominant criteria for lens choice. Some final comments: Flare appears very well controlled in all three lenses, and none was detected. Color-cast is Leica-neutral in all three lenses, and contrast appears identical in all three lenses. For those of you interested, I will state that IMO (totally subjective) the bokeh on the 21A and the 24 is smoother than that of the 21P.

In answer to the original question, knowing what I now know, I will probably sell both 21’s and keep my 24… Anybody want a 21A or 21P? :-)

-- Jack Flesher (jbflesher@msn.com), August 22, 2001

Answers

Thanks for the valuable insights, Jack. But before you ditch both 21's what about those times when you want that "little bit of extra spread?"

-- Bob Fleischman (RFXMAIL@prodigy.net), August 22, 2001.

Thanks, Jack. Very clear descriptions.

Shades of Jay's experience with the 135 APO vs. the plain TeleElmar.

As an owner of pre-ASPH everything, including the 21, I am gratified to know I'm not missing that much. It seems that there is no particular reason to 'upgrade' to the newest Leica lenses except for the 35 'lux and 90 'cron SAA, where even I can see the difference.

I'm looking forward to inspecting, and reporting on, my Konica vs. Leica and 90TE vs. 90EM film even more now.

Interesting that you found identical color rendition - my 1989 21 is about 1/2 of an 81a warmer (yellow) than most of the current lenses, including the 21A. My late-80s 90 'cron was also warm - I wonder if something was going on with one of the glass mixtures from that era, or if there is some kind of 'aging' that takes place - like a lot of time in a hot car trunk or something (I don't know their history prior to last March). I've seen some mention of R lenses randomly showing this as well.

I'm also a little surprised by the 21P appearing sharper in the corners than at the center - mine is center sharp at 2.8 with weak corners, which sharpen up by 5.6-8. I especially noticed this when I compared it to the G-Contax 21, which was equal in the center and 3 times as sharp at the corners at 2.8. I've always sort of assumed the 21 ASPH looked like the Zeiss - much improved corner resolution.

Thanks again...

-- Andy Piper (apidens@denver.infi.net), August 23, 2001.

The biggest issue between the 21/2.8 and 21ASPH at the wider apertures is vignetting. The 21ASPH gives a more even illumination. It also takes an E55 filter, which is a small but nice improvement. As a photojournalist lens, the 21ASPH might be the preferred lens. But as Jack points out, for the landscapist, the performance at f/5.6 or slower is most important. Unfortunately I hadn't taken that into account before lens lust overcame me, or I doubt I'd have bought the 21ASPH, either. However my preference (and the lens I still use for travel and landscape) is the 21/3.4 S/A because of its diminutive size and light weight, coupled with better performance overall than the 21 non-ASPH and at least equal to the 21ASPH (though a bit more vignetting at full aperture only). Of course the main drawbacks to that lens are non-metering with M6 and prices inflated by collectors. For those reasons I am seriously looking into the new 21/4 Cosina. If that lens turns out to be a winner at f/8-f/11 I'll be parting with my 21ASPH.

-- Jay (infinitydt@aol.com), August 23, 2001.

Bob: Well heck... now there's a good point! Seriously, here is my catch-22 dilemma in the 21 v 24 war: I can't imagine my ever actually carrying both the 21 and the 24 in my bag at the same time; I like the 21 to be sure, and it probably makes more sense than the 24 when you consider that my 3E is almost always with me and it has a 28 position; BUT the 24 is just so darn good I hate to part with it; And I can't imagine my ever carrying both in the bag at the same time...

Andy: Yes, I was surprised too at the 21P performing better at the corner than the center, which is why I postulated the curvature/focus issue. However, it seems that was not the case, as the situation reversed itself at smaller apertures, and I made no focus adjustments during the test. As for color balance, I too had also assumed the "older" lens would have that 5 points of yellow extra warmth that seems to be present in many of the older Leica lenses. But it is not there - at least that I could detect.

Jay: In my particular 21P sample, the eveness of illumination is excellent, and in fact at f2.8 both lenses appear identical. At f4, I can detect a slight amount in the 21P, but as you point out, less (just a hint) in the 21A. At f5.6 there remaines a hint in the 21P and none I can detect in the 21A. (Also, to my eye, the 21A actually outperforms the 24 here by a very slight margin.) Like you, I'll be awaiting performance reports on the VC 21 as well.

-- Jack Flesher (jbflesher@msn.com), August 23, 2001.

My two cents, Although I haven't used the 21asph or the previous 21 I did own the 24 asph and found it to be a tremendous performer however I found the lens to be bulky and as others have mentioned a bit short in certain situations. I now use the 21 Super Angulon and although it doesn't meter with my M6's, it's the perfect compliment to my M4. I find that the performance is comparable to the asph lenses and I like the fact that the sa focuses closer than the others and is a much smaller lens. For me the 21 SA fits the parameters nicely for what I like to shoot. Sometimes old works better than new.

T. Gallagher

Regards, Tom Gallagher

-- Tom Gallagher (tgallagher10@yahoo.com), August 23, 2001.

Jay and/or Tom:

Can you quantify at which apertures and in which parts of the frame the SA beats the 21 pre-ASPH?

I'm not skeptical, just interested. Since both my M bodies are pre- metering, the deep rear element wouldn't be an issue. I have heard the 21SA had mean flare and fall-off esp. @ 3.4.

And as this site has demonstrated again and again, lens design for the Leica has NOT been a case of "Always upward and onward."

-- Andy Piper (apidens@denver.infi.net), August 23, 2001.