Leica M full frame CCD sensor camera DIY prototype - with pictures!

<p>The above link is very impressive, especially the attention-to-details during the testing. I need to learn from that for my own testing procedure.<br>

Lens selection wise, I am more interested to know the image circle coverage of each Leica M compatible lenses. Especially, Zeiss ZM wide angle makes me very curious. It would be very interesting to know their performance under full frame.</p>

<p>Probably stupid questions, but...<br>

Mounting a full frame CCD sensor behind the lens in the traditional way doesn't allow for enough room when using lenses on the Leica M mount, right? So, I wonder if there is way to mount a thin mirror where the usual film would be and then bounce the light to a location where the full frame CCD sensor could be located. <br>

And...Why can't manufactures just the make the camera body "thick" enough to accommodate a full frame sensor and the Leica M mount?</p>

<p>Bob, maybe you can take a look at this link: Camera Mounts Sorted by Register <a href="http://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html">http://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html</a><br>

Ideally, there should be just one universal mount specification for all 135 cameras. But the manufacturers just don't want their cheese to be moved away.<br>

The practical value of my testing approach is: if you can use this method to test all your expensive Leica lenses, you will be able to know which lenses work well under full frame and which ones don't. So if the Leica or Zeiss Ikon full frame camera ever comes out and becomes popular, you may want to sell off those not working lenses ASAP, as their second hand value may go down big time. </p>

<p>Couldn't you, just to test the 35mm in daylight, remove the shutter, put some NDs in front and use a lenscap or black cloth as shutter?</p>

<p>Hi Yongfei! I am really enjoying your project! I think you should start a weblog about it. I will certainly follow what you're doing.</p>

<p>Maybe an idea to test your 1.4 in daylight: there are manuals from the early 20th centrury on how to make a shutter out of wood (yes, wood!) with a fixed shutter speed of around 1/30 s. They are meant to go in front of the lens. In combination with a strong ND filter (because the daylight will be too bright for 1/30 at f/1.4) this could be the way to go.<br>

Or if your ND filter is strong enough: no shutter at all, use a lenscap as a shutter. But make sure you can mount your camera on a tripod.<br>

Keep up the good work!<br>

Willem</p>

<p>As promised, I tried to do some more testings on 50mm Summicron and 35mm Summilux. It is a very difficult task. It took me a total of four hours to get a few usable pictures. Focusing is purely a matter of luck. Last time, I got sharp pictures with 35mm even at 1.4, but the lighting was too strong. This time, I got very good luck with 50MM, but not so with 35mm.<br>

Sunpak 120J was used as flash (on the left side). Shutter was only used to trigger the digital back. Shooting needs to be in total darkness for the back to come into "ready to shoot" status. So I have to restart the Eyelike capture application almost after each shot.</p><div></div>

<p>As you can see, the depth of field is very shallow. That could be because the lens is not totally evenly "mounted". So it effectively becomes a tilt lens. Here is the 100%.</p><div></div>

<p>Another 50mm, forgot the F stop. Should be below F5.6</p><div></div>

<p>Here is the 100% crop</p><div></div>

<p>35mm is a total miss. But fortunately, I got a sharp picture last time. I just post here a F5.6 result. It is still out of focus.<br>

With those pictures, I think I have completed my Leica M lens full frame testing effort. It has been a fun experience. And I am glad that I can share those findings with a wonderful group of people who are passionate Leica lovers.</p><div></div>

<p>Sorry I took so long to respond - offline on the high seas for a week.</p>

<p>"In what way would the new lenses be more accommodating to digital sensors Andy?"<br>

<br /><br>

First design them more like an SLR 14 or 20 or 24 - with lots of back focus space. Then increase the diameter of the rear elements to be larger than the sensor diagonal. And then make the rear element(s) something of a transfer or corrector lens that redirects the image to project straight backwards onto the sensor.</p>

<p>Doing each or all of these make the light rays travel more directly into the face of the sensor, rather than outward at an angle from some central pupil-point in the lens. This lets the light travel straight through any microlenses into the "wells" of the silicon that are light sensitive, instead of being offset and hitting the walls of the wells (Think of a city street shaded by tall buildings in winter, but brightly lit at noon on a summer day).</p>

<p>"Digital" lenses would still work on film, so there's no reason they can't perform on an M7. Their drawback, if any, would be that they are generally quite big compared to Leica's film lenses, for the same focal length and aperture. (compare a Canon 20mm f/2.8 with its 72mm filter size to a Leica 21mm f/2.8 that only requires 55mm diameter, or the really old Superangulon f/3.4 that used 49mm filters). And that they require an extra bending of the light rays in back to push the wide-angle image back to parallel rays, which likely means additional aberrations that then ust corrected themselves.</p>

<p>Yes, Leica's lens range generally works well on the CROPPED M8 sensor. But we're discussing a larger sensor in these experiments.</p>

<p>Note that the DISTANCE from the lens to the sensor, in and of itself, is not the problem - there are lenses in small digicams (including the Leica Digilux 2) that practically touch the sensor at all "focal lengths" But they are designed to catch the incoming image and point it towards the silicon perpendicularly, whereas legacy film lenses tend to spread out the image.</p>

<p>Leica's new 21 and 24 designs tend towards those attributes that favor digital (without discounting film) - larger rear elements to physically cover the whole image area from in front (goes along with the f/1.4 apertures) and longish tubular "light pipe" internal layouts to keep the light generally moving parallel in the first place.</p>

<p>Yongfei, what atr those amps you're using w/your hifi?</p>

<p>On my Hi-Fi system, the amps are Stratos <a href="http://www.odysseyaudio.com/">http://www.odysseyaudio.com/</a> and Audio Note Kit-1. And I am using Lavry DA-10 D/A converter with volume control as the pre-amp. The loudspeaker is a DIY design after Dynaudio Contour 1.3.</p>

<p>Thanks Andy.</p>

<p>

<p>There have been a few discussions about this project on some internet BBS . Obviously, some of the guys didn't read the whole thread. So I'd like to post some of my conclusions here:<br>

- There are multiple purposes associated with this experiment. At the beginning, I want to put things together just for fun. Later on, I became quite curious about the performance of my Leica 35mm/1.4 on a full frame CCD. Because if the image quality is not good, I will sell it before its resale value starts to go down.<br>

- I tested Leica 50mm F 2.0. There is no obvious problem with this lens on a full frame CCD.<br>

- I don't have any Leica wide angle lenses, so I tested a Sigma 24MM SLR lens. The full frame result is quite good. So I can't say if the Leica/Zeiss wide angle lenses will work or not on a full frame CCD.<br>

- In the current configuration, I use a Copal shutter behind the lens. So sometimes the total distance is to far for infinity focus. The real M type shutter will not run into this problem. But to put a digital back on the M camera at the film plane rail, is very easy to scratch the CCD.</p>

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