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Contax Digital in YC Mount

Thanks again, Lynn. I agree with you that it's very valuable to see other people's work. I for one would like it if more members of discussion forums "put their photos where their mouth is". I don't mean that in a nasty way. I just mean that "seeing is believing". It's the best way to cut through all the differing opinions when it comes to cameras, lenses and film.

I love Astia because it scans so beautifully. I originally tried Provia 100F but could rarely get a good scan that I was happy with. Provia scans often have a colour cast according to the type of light in the scene, whereas I found Astia to give reliably accurate scans which required minimal colour correction. In particular, Astia reproduces skin tones and whites really beautifully. I've never used Sensia myself, but one of my students shot a roll of Sensia and a roll of Astia on the same trip (Guest Photographer 1 on my site) and I could see a difference between the Astia and Sensia slides on my light box. The Astia yellows were more punchy than the Sensia, which leads me to believe that they are not the same film stock.

Just to get us back on to the original topic of this thread: Contax digital in Y/C mount, I'd be happy with a sensor that was less than full frame size, as long as we could move the sensor up and down inside the camera, taking advantage of the lens's larger image circle, to achieve a "shift" function for perspective correction.

I'm surprised that no digital camera yet allows "sensor movements". It would mean we could enjoy tilt and shift effects with standard lenses. What do you think?

Kind Regards,

Craig
 
Thanks very much for the info Craig. I'm about to order some film, and will include some Astia this time. (By the way if anyone knows of a better priced source that sells well stored film in the US than B&H please email me at Lynn@turnkeydesign.net) I want to put at least a page of photos together, and will do so soon. At the very least - images from my Contaflex and later from another classic I have my eye on but don't own yet. I find especially with these old cameras many people talk about them, but few post images. Anyway - thanks again.

And for the record, in case I didn't reply when Clive asked whether anyone else would be interested in such a development (digital for c/y or other cameras) - count me in. If it could be done and done well, yes I would be interested. -Lynn
 
Rico, that's a nice demonstration of lens tilt.

I'm curious about why you think the need for shift is eliminated by a digital workflow. Are you referring to the perspective correction feature of Photoshop? If so, I must state my dissatisfaction with that solution. I think it is a poor substitute for a real lens shift function. I've used Photoshop's perspective correction several times, and while it is sometimes possible to "get away with it", there is a noticeable loss of detail, and the need to crop the image after perspective correction is sometimes undesirable because it ruins the framing that I chose when I took the shot.

Do you have a better solution that truly obviates the need for lens shift, without loss of quality?

Regards,

Craig
 
Craig,

The PhotoShop method of perspective control may stretch a portion of the image resulting in it looking odd. I think that what actually occurs is the the pixels per inch of the stretched part of the image is effectively reduced and interpolation occurs to compensate.

A perspective shift lens does not perform the same task. It merely shifts the image circle up or down on the film plane. It is very much like if you had taken a wider angled shot and later cropped it.

Some view cameras have a tilt and swing function on the film back. This has the same effect of the PhotoShop perspective function but without the stretched pixels effect. Downside is that the depth of field differs in one side of the image to the other, although this can be used to creative effect.

Clive
 
About this tilt shift discussion. Just a side note: if anyone needs to remember how to do these things the traditional way on a view camera, just take a look at Ansel Adams book "The Camera". He does a wonderful job of making it make sense, of course it is illustrated to make it simpler. I don't often get the chance to use a view camera any more, but when I do, I pick up the book and remind myself where everything is and how it all functions. They're wonderful things - view cameras. -Lynn
 
Clive, I get your meaning completely, and that is the same meaning I was trying to convey in my post.

A shift lens allows one to photograph tall buildings with a wide angle lens, while pointing the axis of the lens above or below the horizontal, without the buildings converging or diverging. I face this problem all the time in Hong Kong. See: http://alkiratech.tripod.com/photogallery/id9.html

A shift lens would allow me to take that picture of the city view from that high vantage point, but have the buildings all appear vertical in the photograph. Shifting a small digital sensor up and down within the lens image circle would give me the same effect without needing a special shift lens. When I tried correcting the perspective of this photograph with Photoshop, the result was unacceptable.

That's why I asked Rico to elaborate on his comment that the digital workflow eliminates the need for a shift lens. I'll be very happy to find out that there is a better way.

Craig
 
Craig,

Two tips which I hope will help;

First - if you distort perspective in Adobe do it at the largest image size before you compress it. That may limit the stretch effect.

Secondly - There is a reasonably priced manual focus 35mm f2.8 shift lens available in various mounts including Canon FD and Nikon F. The venerable Russian Arsat! Independent reports suggest a good image quality. They can go for less than $150 on eBay. You may be able to mount that on a digital camera.

(Those of you who have suggested previously that I do not know my Arsat from my Elmar may now wish to reconsider).

Clive
 
Craig,

When applying shift digitally, pressure is placed on the image already collected. As you point out, this may produce an unacceptable result resolution-wise.

The analog shift movement captures an image from the poorer part of the image circle. One must assess light fall-off, CA, and other aberrations nearer the edge. A larger image circle is needed, and that means heavier glass.

Either way, the correction can be over-applied, resulting in an artifical effect. While sometimes necessary, shift is not a proper solution for bad perspective - it's always preferable to position the camera at the correct elevation.

As for framing, digital and analog shifting requires a larger AOV to reframe. For analog, the reframing is done in-camera while, for digital, reframing occurs in post-processing. I admit, digital capture is tricky because you can't visualize the frame needed for the capture.

In summary, I tilt to digital for shifting
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Clive, thanks for the tips.

Rico, thanks for the clarification. I get your point now.

Cheers,

Craig
 
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