Leica 18mm f/3.8
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These two lenses do the same thing on the same cameras.
So which is better?
I'm shooting full-frame.
I'm ignoring the little half-frame sensor of the Leica M8.2.
For the M8.2 and the Leica 18mm, you use a special UV/ IR filter 13 422 that screws in between the lens and its small included hood. Of course this Leica hood is pretty worthless with the M8.2 because the M8.2 only uses the center of the image, so the hood blocks very little of anything other than your fingers.
I'm not considering the M8.2, the UV/ IR filter 13 422 or the included hood here.
With either lens and the M8.2, you use a 24mm viewfinder, not an 18mm finder.
The Zeiss lens takes 58mm filters as shipped. Except for your choice of color, the Zeiss lens only comes one way: the way you see it above. This is good.
The Leica lens requires you buy an additional $100 77mm filter ring so you can use filters as shown above. Otherwise, all you get is a lens with a hood but no way to attach any filter. This is how the Leica lens looks without its hood or filter holder:
Leica 18mm, no hood or filter ring. enlarge.
As shipped, the Leica lens has a small hood that screws over these external threads. To use the Leica lens with filters, you remove the small hood and replace it with the 77mm filter ring that screws over these same external threads.
Everything I'm saying here is including this filter ring on the Leica lens, which is mandatory presuming you want to take pictures on anything other than color print film.
Thank goodness the Zeiss lens just works as shipped.
The biggest differences between these lenses are how you use filters and how they block your viewfinder.
They are almost identical optically. The most significant optical difference is that the Zeiss is warmer than the Leica (or the Leica is cooler than the Zeiss) by about one-half to one-quarter the strength of an 81A filter.
Color Balance top
The Zeiss is warmer, while the Leica is cooler.
The difference is about a quarter or a half of an 81A (A2) filter.
The Zeiss is specified a bit better, but neither manufacturer specifies the distance at which they're specifying this.
On film, the Zeiss has less distortion at 10 feet and closer. They are about the same at longer distances.
The Leica tends to have an undistorted (flat) center and pincushion distortion at the sides (the center is OK and the sides tend to pull-out).
The Zeiss tends to be flat at the sides and bulge a bit (barrel) in the center.
Overall, it's a toss-up depending on your subject distances and what part of the image you worry about most.
If you're only using the center of the image by shooting an M8, the Leica lens might be better at close distances.
Each has a healthy amount of falloff. The falloff doesn't change much as stopped down.
The corners are supposed to get darker with an 18mm lens on a rangefinder camera.
The Leica has a little less falloff. Especially wide open, the corners aren't quite as dark with the Leica 18mm.
Focal Length, actual top
Images from the Zeiss 18mm are about 0.8% larger in magnification than the Leica 18mm.
Thus the Zeiss is a tiny bit longer.
Use any 18mm finder with either lens. They are all sold separately.
The Zeiss 18mm finder is superior to the Leica finder. The Zeiss finder is bigger, brighter, and most importantly, has only one rectangle for the 18mm frame line.
The Leica finder is defective in design because it includes frame lines for a 24mm lens inside the 18mm framelines. This was done as a marketing gimmick to sell the 18mm lens to M8.2 owners, whom Leica didn't want to remind that they really only needed a 24mm, not 18mm, finder.
Don't fall for it. Use the Zeiss 18mm finder.
Finder Coverage top
The Zeiss 18mm finder is very cautious. You get generously more on film than it shows in the finder.
The Zeiss finder covers just a tiny bit more than a 21mm lens gets on film. In other words, the Zeiss 18mm finder is just a little too loose for a 21mm lens, and you'll get more on film with an 18mm lens than shown in the Zeiss 18mm finder.
I haven't had the Leica finder long enough to gauge its 18mm coverage. Other Leica finders tend to be rather unforgiving.
Since finders are never perfect, they almost always show less than you'll get on film since they rarely adjust for distance.
Finder Blockage top
The Zeiss lens blocks a lot less of your finder. Skip the hood on the Zeiss, since you'll see all of it in the bottom of an 18mm finder.
The Leica is worse than the Zeiss, but not as bad as I had worried because the cut-outs in the filter ring let you see the bottom of your image just fine.
The outer ring of the filter ring can drive you nuts since is does loop up and around in the bottom of your finder, but thankfully this isn't a deal-breaker as I thought it would be — unless you're using a dark filter.
Filter Reflections top
None from the Zeiss. Its filters mount the usual way.
Be careful with the Leica: light from behind the camera can bounce off the back of the filter back into your 18mm lens and appear as ghost images on the top corners of your image! Be especially careful with the Leica 18mm and darker filters, since these are more likely to show reflections.
Peripheral Color Shift top
I see little color shift in the corners.
I see more overall falloff than color shift, which is good. There is less falloff in the Leica, but each has about the same color shift.
f/3.8 is only one-sixth of a stop faster than f/4.
f/3.8 was designed by Leica for marketing, not for photography.
Yes, f/3.8 does meter a little bit lighter than f/4: just 1/6 of a stop as expected.
Film isn't manufactured to this level of accuracy; don't pick one lens or the other based on speed.
I shot Fuji Velvia 50 from on top of a mountain on a clear day with no wind and no heat shimmer.
I used a tripod and pointed it down so that the entire image were objects at least a quarter-mile (500 meters) away.
I then looked at the slides in a Nikon Alphaphot YS biological research laboratory microscope with a stereo head at 40x magnification with the condenser all the way open. This microscope goes to 1,000x magnification; 40x is its lowest power and enough to render the grain more sharply than any photographic process. At 40x, one can see everything that's on the film.
It's a tie. Either of these lenses is so good that I can't see any repeatable difference. In some cases the Zeiss seemed a bit sharper wide open in the corners, and other times the Leica seemed a tad better.
They are so close that I can't see differences between the slides shot directly against each other at the same time, much less proclaim either as the winner.
Anyone who claims either one is sharper clearly isn't using a valid target (brick walls show more about how well the camera or rangefinder is aligned than differences between lenses), doesn't have a real microscope (loupes aren't sharp enough and don't magnify enough), or didn't have both lenses to shoot the same targets at the same time, or worse, shot them on different days or with different subjects. If you actually shoot both under controlled conditions, there is no repeatable difference even wide open.
I was all excited about showing comparison clips, but there isn't any difference, so screw it. I'm not going to hook up a digital camera to my microscope to show nothing. 3,600 DPI scans show even less.
If you need sharper photos, you need a medium or large-format camera to make any improvement. Either of these lenses is as good as it gets in 35mm, and far better than any fixed SLR lens like the Nikon 18mm f/2.8 AF-D.
Comparison Tables top
* Included hood works only with no filter, or with the dedicated UV/ IR Filter 13 422, only.
* * Including necessary, but optional, $100 77mm filter ring 14 484.
* Leica specifies 18.3mm. I derived the effective focal length of the Zeiss lens by comparing on-film sizes of images of objects at infinity which covered approximately 35mm across the horizontal dimension of the film.
Focus and Materials top
* Your camera's rangefinder probably only couples to 0.7m, but these lenses focus this close even if you lose rangefinder coupling.
Optics are the same. The Zeiss is a tiny bit warmer, which I prefer. Each is exactly as sharp as the other. Distortion varies a bit, but neither is obnoxious.
Ergonomically the Zeiss works better with filters and blocks the finder less, while the Leica weighs a tiny bit less and feels better in-hand because the huge 77mm filter ring keeps my fingers out of my picture.
The Leica feels better on-camera, but feels awful in a bag. The huge 77mm front means it won't fit where I might like to stash it, while the Zeiss will fit. (The Voigtländer 21mm f/4 is almost as sharp, has less distortion than either of these lenses, weighs less than one-half as much and takes 39mm filters.)
The Zeiss is easier to drop. It's smaller and slightly heavier. The Leica feels more like air, and it's easy to hold with its fat 77mm front. The Zeiss is more like a small slippery brass cannonball.
I haven't even considered price. If price matters, forget the Leica. The Leica costs almost three times as much. Zeiss makes its lenses far more efficiently than Leica, so you get a better lens for less money. Of course the Leica man settles for nothing less than the LEICA, and the Leica 18mm feels more harmonious if you're using a Leica camera.
If you use the Leica, be careful about reflections from the back of the filter.
With either lens, I'd toss the included front caps and use a Nikon 58mm front cap or Nikon 77mm front cap. These latest Nikon caps come on and off much more easily than the Zeiss cap, and the Leica doesn't come with a 77mm cap anyway!
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The biggest help is to use these links to Adorama, Amazon, B&H, Calumet, Ritz and J&R when you get your goodies. It costs you nothing and is a huge help. These places have the best prices and service, which is why I've used them since before this website existed. I recommend them all personally.
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