21mm M-Mount Lenses on the Leica M9

There is an interestingly broad selection of lenses in the 21mm focal length for M-mount cameras.  Neither Canon nor Nikon make 21mm primes for their SLR’s, and both only have one similar prime in 20mm.  The Leica M user has a broad selection of 21mm lenses in current production:  From Leica we have the 21mm f/1.4 Summilux-M ASPH., the 21mm f/2.8 Elmarit-M ASPH. and the 16-18-21mm f/4 Tri-Elmar-M ASPH. (popularly known as the WATE), while Zeiss offers the Zeiss 21mm f/4.5 C Biogon T* ZM and the 21mm f/2.8 Biogon T* ZM; finally Voigtländer has the 21mm f/4P Color Skopar.  It’s an embarrassment of riches–and that’s not even counting the older discontinued lenses in the focal length that are still 100% compatible with the M9.

But how do you chose one for your use?  There’s a wide range of prices, from the eye-watering $6,495 for the 21mm Summilux, to the bargain-priced Voigtländer at $419. Obviously, if you need speed, the Summilux is the only choice–in fact, it’s the only f/1.4 21mm lens, period.  But at f/2.8 and f/4, you have several choices, and the price range is still pretty broad–the Elmarit-M ASPH sells for $4,395, and the Zeiss f/2.8 Biogon lists at $1,340 (Interestingly enough, while checking prices just now I see that B&H lists the Elmarit-M ASPH. as “Discontinued” and Adorama doesn’t have it on their site–but Leica still lists it, and some resellers still have it in stock).  Similar choices exist at f/4.

I decided to compare a few of these lenses that I have on hand.  While I would have liked to include the Zeiss lenses, I didn’t have easy access to any copies for inclusion in this testing.  I have briefly shot with the both of them, and I can say that the 21/2.8 is excellent, and can be used with ease on the M9, whereas the 21/4.5 suffers from some very strong red edge effects.  Perhaps I can get copies of these lenses in the future and update this review.  Following is the comparison shot I was able to do, using the Voigtländer 21mm, the Leica Elmarit-M ASPH. and the WATE.  As with all of these comparison images, click on the image to go the Flickr page that with the “Large” image, and then select the link for “Original” size to see the 100% pixel-level comparisons:

These images were all shot within a few minutes of each other, and the full-sized jpegs can be found here.  The shots were normalized for white balance and that was about it.  The camera was on a tripod and after each lens change a small amount of focus bracketing was done to ensure optimal focus.

Observations

All lenses are to some extent compromises.  For example, if you want to have extremely sharp performance from center to edge, then you will have to introduce some distortion.  The digital age adds some new twists.  Let’s walk through the three lenses.

Voigtländer 21mm f/4P Color Skopar

In the case of the Voigtländer 21mm, we have a very simple design with minimal distortion and excellent performance from center to edge, with all but the very extreme corner being very sharp, even wide open.  In fact, of the three lenses reviewed here, it was the sharpest on center wide open.  However, it suffers from a pretty bad case of “red edge” on the M9.  To correct this, you will have to use CornerFix and follow the procedures I outlined in an earlier blog posting on using the Voigtländer Ultra-Wides on the M9.  I have a gallery of images I took with the Color Skopar on Flickr; you can see them here.  You can see a number of image pairs that show before and after correction with CornerFix.

UPDATE:  Not long after I wrote this review Leica released a new version of the firmware for the M9–version 1.162–that was designed to further correct issues with color shift (i.e., “red edge”) with their lenses.  Not only did this firmware address the red edge issues that remained on a few Leica lenses, but it also allows the 21mm Color Skopar to be used without having to resort to CornerFix.  Simply code the lens manually as the Leica 21mm f/2.8 Elmarit-M pre-ASPH (11134).  While occasionally some residual color can be seen in the far lower left corner, it’s very uncommon.  As a result, I’ve picked up a copy of this lens for when I want a small light wide with minimal distortion.  Version 1.162 firmware has since been superseded by 1.1.74, which has all of the same color corrections and also addresses some SD card problems.  Use either version with confidence with this lens.

Leica 21mm f/2.8 Elmarit-M ASPH.

This lens has apparently been recently discontinued.  While the Leica website shows it as a current lens, B&H is now showing it as “Discontinued” and its disappearing from stock elsewhere.  Perhaps we shall see a redesign?  Regardless, this is a very nice lens.  It’s not as sharp on center as the Voigtländer or the Tri-Elmar, but its quite sharp in the center wide open.  The far corners are slightly soft until f/5.6.  It has slightly more distortion in the corners than the Voigtländer, and in the full-sized shots you can see that its a complex distortion, although mostly just barrel distortion.  I personally like the color rendering of this lens; it’s fairly high contrast and produces very rich colors on the M9.  To me this is a compromise lens–relatively fast and compact at a reasonable price.  The extra two stops you get with the Summilux cost a lot of money and the result is also a much larger lens.

Leica 16-18-21mm f/4 Tri-Elmar-M ASPH.

The last lens in this group is actually Leica’s only true zoom lens (the 28-35-50mm Tri-Elmar-M was three primes in one).  As you might expect, a wide zoom requires more complicated optics and the potential for higher distortion.  Indeed, this lens has the greatest amount of distortion of these three.  That said, the distortion is just a very mild barrel distortion, although it does increase as you click it to the wider focal lengths.  This lens is very sharp from the center to the edges and is just a tiny bit behind the Voigtländer in the center wide open; its the sharpest in the corners of all of the lenses in this test.  I personally love this lens, and if I don’t need the extra stop of the Elmarit, this is the lens that I will have on my camera.  The Universal Finder (affectionately known among Leicaphiles as the “Frankenfinder” due to its large size and array of knobs) is very good and a must-have with this lens.  While you can buy the lens without the finder, I recommend buying the bundle as you will save several hundred dollars on the cost of the finder.

Conclusions

The 21mm focal length is an interesting one.  It’s much wider than many people might realize; the FOV on the M9 is 84 degrees for a 24mm lens, and jumps to 92 degrees at 21mm.  To me its often a “just right” focal length when it comes to wide view–the distortion is low enough that it still seems natural to me.  I frequently use this focal length when shooting architecture and cityscapes.  I don’t think you can go wrong with any of the lenses here, but you do have some choices.  If you don’t want to deal with correcting your images in CornerFix, then you will want to avoid the Voigtländer.  However, its such an inexpensive lens and has outstanding performance, so I would urge anyone considering this focal length to give it full consideration.  If the 21mm f/2.8 Elmarit-M ASPH. has been discontinued, then the options are limited in the Leica camp–either the incredibly expensive Summilux or the WATE.  If you don’t need the low-light performance, the WATE is a great lens.  If I could have only one wide lens on the M9 it would be this lens.  I should note that as of this point, some M9’s will get mild red edges with this lens in some conditions.  I have had two M9’s and the second one gets red edges in certain conditions with the WATE, especially at 16mm.

Acknowledgments

I want to thank Stephen Gandy of Cameraquest for loaning me the Voigtländer 21mm f/4P Color Skopar used for this review.  While I have owned a Voigtländer Color Skopar in the past, I currently don’t have room in my bag for two f/4 21mm lenses, and the WATE wins out for sheer utility.  If you are looking to buy any Voigtländer lenses, I highly recommend Stephen.