Sinar F and P45

[Grayhand]

Hi!

I have a RZ system with a P45 digital back.
I have now bought a Sinar F in ”as new” condition with a Symmar 210/5.6 and a Symmar-S 150/5.6 and accessorise for film, both 4*5 and 67.
The system is now working digital whit help of an Digital Art Institute sliding back for my P45.

But with the digital back I have a system for telephoto
It is ruffly a factor of 1.4 longer compared to a 35 mm system -> the 210 is ruffly a 300 mm lens on my 1Dsll.
What alternative does exist, for a reasonable cost, if I would like to get close to 50 mm(35) and that also is usable on 4*5 film, no fish eye effect.
Or is it 65 to 75 mm that is reasonable and I should be satisfied with 100 mm(35) coverage?
I dont find any information on lenses and digital backs.

Ray

[dwhistance]

Shouldn't you be dividing by 1.5 rather than multiplying given that the P45 chip is larger than that of the 1DS? If I am right then I think your 210 is more like a 150 (if it existed) on the 1DS?

If that is the case then you need to look at lenses around 65-75mm with the P45 to give you the equivalent of a 50mm lens on 35mm film. There are lots of lenses at these focal lengths that will cover 4x5 film (with minimal movements), however they are probably not the best lenses to get the highest quality from your P45.

If you want to use the Sinar with film as well as the digital back then I suspect you will have to invest in two sets of lenses - one for film and one for the digital back.

David Whistance

[Grayhand]

Thanks for the answer.

No, I compare the Sinar with 210 mm and P45 to my 1Dsll.
The 210 givs then ruffly the same view as a 300 mm on 1Dsll.
The P45 is very small compared to 4*5.
I have made practical tests

Do you mean that the ordinary 75 mm LF-lenses have low quality?
A small image cirkel is no problem with the P45 I think, due to its small size.

How small LF-lenses can you use before you get fish-eye or similar effects?

But I am afraid that you might be right that i need two sets of lenses.

Ray

[dwhistance]

I thought someone else might have chipped in by now, however here goes again.

The P45 chip has dimensions of 49.1x36.8mm according to the Phase One website. The 1DS is a "full frame" dslr so its chip will have dimensions of roughly 25x36mm. There is therefore no way that a 300mm lens with the 1DS could give the same field of view as a 210 with the P45. I suggest you check your tests, practical or otherwise.

As far as the lenses are concerned the 65mm and 75mm large format lenses are high quality but were designed to be used with film. You may well find that you get colour fringing and other chromatic aberations when using them with a digital back with a Bayer filter. Lenses designed to be used with these digital backs minimise these problems at the cost of a much reduced image circle. Unfortunately this limits their useablity with LF film.

David Whistance

[Bjorn Nilsson]

There is a difference in how lenses for digital backs are built and "normal" lenses for film use. Digital seems to like higher contrast, but there is little difference to modern film lenses.
Anyhow, "ordinary" decently modern LF lenses will certainly do the work. You can also use just about any lens, down to the 47mm Super Angulon XL from Schneider (which covers 4x5") or even the 35mm Grandagon from Rodenstock which is intended for a maximum filmsize of 6x9cm or so. None of these lenses will give you any strange fish-eye effects. But you cannot use much shift either, as digital backs are a bit fuzzy about the angle at which the light hits the sensor. I think that the digital range of lenses from Schneider and Rodenstock are constructed with this in mind, so that the lenses are further away from the sensors than the classical type of wide angle lenses. These lenses are also optimized to be at their best at wider f/stops than normal LF lenses. (f8-11 as opposed to f/16-22.) Last, these lenses are of course made to be at their best with a view camera, but they normally don't cover 4x5".
If you are serious about your work with large format digital photography, I recon you do need to have a look at those special digital lenses, but for starters any decently modern wide-angle lens will give you what you need.

//Björn

[Grayhand]

Well, it is always irritating to have to admit that I am wrong
I made it all over again with 2 tripods and did take actual photos with both the Sinar, RZ and 1Dsll.
To many confusing lines on the focusing glass
The new multiplication factor is ruffly 0.75.

Thank you for your clarity, David. It saved me from some mistake.

Now it seems that 67-75 mm on the sinar is exactly what I am looking for

Becaus my back does not have micro lenses, I suppose that shift is not that big a problem.

Thanks for the help
Ray

[neil poulsen]

I spoke with a Schneider LF technician, in fact a couple of them, regarding the use of standard S.A.'s (like the 65, 75, etc.) or the Symmar-S or Apo Symmar S lenses with digital backs.

They both agreed that at 22 megapixels, the standard lenses should be just fine. However, one would see a difference between using the Digitar or standard lenses above 22 megapixels. The Digitars would be better.