Is your 28mm Elmarit-R 2.8 really sharp in the corners?

<p>I recently bought a Leica 28mm Elmarit-R 2.8 ROM (Latest version) to use with my Canon 5D Mark II.</p>

<p>After reading so much about the incredible performance of this lens I decided to get one for my Full Frame DSLR.</p>

<p>So many people claimed that it was sharp corner-to-corrner even at large apertures.</p>

<p>Unfortunately, this was not my experience. I found that the corners are considerably unsharp and soft even at f/5.6.<br>

They finally improve at f/8 but are not, "sharp".</p>

<p>If anyone out there has this lens and a Full Frame DSLR, I would very much like to hear a contradictory report from them.</p>

<p>However, if they take a photo - preferably of buildings - at f/5.6 or f/8, focused at infinity, they will be equally surprised and disappointed if they look at the corners at 100% magnification.</p>

<p>I would really like to be proven wrong.</p>

<p>Can't say about digital, but on film mine was amazing. They do have field curvature so they are not good for flat surfaces up close. Either yours is messed up or they just don't "go" well with the camera.</p>

<p>Carlos,<br />I suspect this is a focussing issue. Are you sure you have it accurately focussed? Is your R-EOS adapter accurate? Are you relying on the chipped adapter for focus confirmation? If so, then I found this insufficiently accurate. I found focussing difficult on the 5D even with the S screen. I found the lens superb on film, but personally I find the transition of the R lenses to the EOS rather unsatisfactory for anything other than super-wide or telephotos due to the difficulty in focussing. In this respect the good old EOS AF lenses are a better match.</p>

<p>Carlos,<br>

I have also found this lens to be a spectacular performer in all respects and apertures. I'm only using film so can't speak for using it on the Canon. Best of luck on finding the cure.</p>

<p>The photos I use to inspect corner sharpness are all focused at infinity.</p>

<p>Is your adapter exactly 3.00 mm thick and are the mounting faces parallel? Was the building at infinity?</p>

<p> If the lens has a small exit pupil, you may have run into a common problem with sensors covered with a bayer and an anti aliasing filter. Light rays striking near the edge of a sensor's filters are diffused to certain extent which increases as the size of the rear element decreases. This diffusion is much more visible on electronic sensors than on film, and is why newer lenses designed for digital imaging systems have much larger rear elements than previous lenses made for film.</p>

<p> </p>

<p>Carlos,</p>

<p>My guess is the adapter is not exactly the right thickness. Try focussing on something only a few feet away and see if you can get it sharp. If so, then the adapter is at fault, if not then your focussing is faulty or the lens is defective.</p>

<p>IMO the 28 is not sharp in the corners, due to curvature of field. Excellent in the center and very good in the edges. Try focusing a bit closer for critical sharpness in the corners. Color and contrast are really amazing (mine is the 3 cam version)</p>

<p>António -- I think the ROM version is an optically updated version compared to your 3-cam lens. It is a very recent design and everyone raves about it (except Mr. Prado!). I would agree with Bob and Robin -- it is more likely that your adapter or your adapter/lens combination is not in exact tolerance. These wide angle lenses are machined to very high tolerances, and when you introduce a generically specified adapter (i.e. not made for that lens/camera combination) and try to use it on a non-Leica body, you are introducing a lot of room for error. It is also unlikely that you will be able to tell if your adapter is out of tolerance by your eye either -- you would need a very sensitive micrometer to measure the thickness and flatness of the adapter. Of course, it COULD be the lens, but that is probably the least likely culprit -- it's most likely the adapter, then just your lens/adapter/camera combination being all at the outside ranges of their tolerances, adding up to poorer than usual performance, after that, it would probably be some problem with the lens mount on the camera, and only if none of those are the case, then is it likely to be a problem with the lens itself. </p>

<p>Check your lens to camera adapter first. If you can invest your money on high quality adapter do so. The adapter thickness is extremely important .The final version of 28mm R is known to be very sharp corner to corner. I've experinced this situation myself.</p>