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Very Vintage Lenses on NEX
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PostPosted: Tue Oct 21, 2014 4:21 pm    Post subject: Very Vintage Lenses on NEX Reply with quote
Hello, it's been a while !
I'll be gifted a NEX pretty soon, if I've laid the clues around well, and have been looking up on vintage lenses out of curiosity. My question is would full, half-plate and brass lenses like the Dallmeyer, Rodenstock work on a NEX and what would the outcome be focal length wise ?
I've searched around but the only info I could find was a guy who posted a pic taken with a Dallmeyer Serrac 2" F4.5 mounted on his NEX-7. Cheers.


PostPosted: Tue Oct 21, 2014 5:50 pm    Post subject: Reply with quote
The focal length won't change, but the field of view will, most APS-C is 1.5x the focal length for an equivalent Field of view on FF(24x36).
Just keep in mind that a lens is designed to have a spicific distance from the imaging plane to reach infinity, how ever you adapt the lens(bellows?) that will be your minimum distance from the sensor.


PostPosted: Tue Oct 21, 2014 8:47 pm    Post subject: Reply with quote
Indeed the crop factor is 1.5 relative to 35mm, I wasn't sure however how to calculate it when the lens was designed for bigger sensors, your reply prompted me to look better. Bear with me !

Using a Dallmeyer 23cm f6 as an example :

The lens was designed to project the image on a 216 × 165 mm glass plate, which has a diagonal of 272 mm.
A sony NEX3 has a 23.4 × 15.6 mm sensor with a 28.1 diagonal.

The crop factor should be 272/28.1 = 9.68x which means the equivalent fov would be 230x9.68 = 2226 mm. Is that right ?

With the image coming from such a tiny area can you still expect to get usable results ?


PostPosted: Tue Oct 21, 2014 9:35 pm    Post subject: Reply with quote
I tested a few very old lenses on NEX. Most of them have flare problems and a big hood is mandatory. The contrast is, generally, low.
Speaking about resolution, the results are mixed. Most of them had to be closed at more than f/8 for satisfactory results but some of them were quite good even at f4.5 - f5.6.
You shouldn't expect them to compete with the more recent 24x36 lenses but they can have their charm.

Some of the ones I've tested, as far as I remember (of course, it's only my opinion):
Good ones : TT&H 3 inches, 3 1/4 inches and 5 Inches, TT&H Aviar 3 3/4 inches, Heliar, Mayer Trioplan 100 mm. f/3,Linhof Technikon, some Petzvals
So-so ones : Kodak Ektar 101 mm., some Tessars, TT&H Aviar 6 inches
Not so good ones : some older Symmars, some Tessars, Rodenstock Doppel Anastigmat Eurynar


PostPosted: Tue Oct 21, 2014 9:55 pm    Post subject: Reply with quote
Most old lenses were designed for larger film formats, so the effect of using them on a modern camera like a Nex is the same as cropping out 95% of the image and enlarging it. Your best bet for the old lens is to use it on a large-format camera and then use the Nex to take macro photos of the negative which you can stitch together in Photoshop.


PostPosted: Tue Oct 21, 2014 10:25 pm    Post subject: Reply with quote
Ellery wrote:
The crop factor should be 272/28.1 = 9.68x which means the equivalent fov would be 230x9.68 = 2226 mm. Is that right ?

No, the crop factor of your camera is always x1.5 (relative to 135) and always will be. So 230mm x 1.5 = 345mm.

Focal length is absolute, the crop factor is purely a conversion back to the equivilant 135 angle of view and large format cameras also have a crop factors - any format larger than 135 format will have a crop factor <1.


PostPosted: Tue Oct 21, 2014 10:37 pm    Post subject: Reply with quote
I have used many old large format lenses on my NEX and my Nikon with great results, You are using the sweet spot in the centre of the frame and old lenses can be remarkably sharp, especially to good makers like Zeiss, Dalmayer etc.. I'd get a cheap M42 bellows unit and NEX adapter and make adapters to fit old lenses to the bellows. A couple of extension tubes will be useful for the longer lenses.

A 23cm lens is 230mm, the field of view will be exactly the same as any other 230mm.

I have stopped thinking about the crop factor, with long lenses, it makes more difference with short lenses. If I use the 18mm end of my kit zoom it is equivalent to a 28mm lens in 35mm (+/-)
but If I use an 18mm lens designed for 35mm on my nex with a focal reducer I get the equivalent of 18mm (+/-) but I digress.


PostPosted: Wed Oct 22, 2014 12:26 am    Post subject: Reply with quote
Thanks for the replies and insight guys, I'll have to follow the digression now since it picked my interest. And don't get me wrong there won't be anything personal in my reply just the will to discuss it further and clarify !

@GeorgeSalt That would be true if the 230mm lens was for a 35mm camera but as you stated larger format lenses imply greater scaling factors, and in this case the lens is for an even bigger format.
You have the crop factor of a large format lens to full frame, and then from full frame to aps-c, so it can't be just 1.5x ? The 9.68x number I found would agree with David in that the image will be 10 times smaller or missing out 90% of the original. Math might be off, it's late !

@philslizzy You anticipated my next question, which was how to mount the lens ! Many thanks.
About the fov, shouldn't it change relative to the sensor size ? When this 230mm lens was used on a glass plate it produced an image with a view similar to what a 50mm lens produces on a full frame, didn't it ?


PostPosted: Wed Oct 22, 2014 11:24 am    Post subject: Reply with quote
Ellery wrote:
@GeorgeSalt That would be true if the 230mm lens was for a 35mm camera but as you stated larger format lenses imply greater scaling factors, and in this case the lens is for an even bigger format.
You have the crop factor of a large format lens to full frame, and then from full frame to aps-c, so it can't be just 1.5x ? The 9.68x number I found would agree with David in that the image will be 10 times smaller or missing out 90% of the original. Math might be off, it's late !

It's not your maths, it's the application of it.

Focal length is constant.

The field of view is a function of the focal length and the dimensions of the sensor plane. But your crop factor of x1.5 relates the equivilent focal length relative to a 135 frame.

Your x9.68 is a crop factor relative to a 7"x5" frame. What this means is that if you wanted to get the same field of view on a 7"x5" camera that putting the 230mm on your APS-C would give, you'd need to fit the 7"x5" camera with a 2226mm lens. Working backwards, my guess is that to get the same field of view on an APS-C camer to the 230mm lens on 7"x5" camera would need a lens about 30-35mm.


But, any 230mm lens onto your APS-C camera will give a field of view equivilent to a 345mm lens on a 135 "full frame" camera. Which is the equivilant focal length that most people are thinking of when they think about equivilant focal lengths and crop factors.


PostPosted: Wed Oct 22, 2014 2:14 pm    Post subject: Reply with quote
GeorgeSalt wrote:


Your x9.68 is a crop factor relative to a 7"x5" frame. What this means is that if you wanted to get the same field of view on a 7"x5" camera that putting the 230mm on your APS-C would give, you'd need to fit the 7"x5" camera with a 2226mm lens. Working backwards, my guess is that to get the same field of view on an APS-C camer to the 230mm lens on 7"x5" camera would need a lens about 30-35mm.


Yes that what I was comparing, just the nex to a full plate camera.

GeorgeSalt wrote:
But, any 230mm lens onto your APS-C camera will give a field of view equivilent to a 345mm lens on a 135 "full frame" camera. Which is the equivilant focal length that most people are thinking of when they think about equivilant focal lengths and crop factors.


Thanks that's a good wording, I'll consider it a 345mm and keep in mind the restricted fov.

Now comes the funnier part, shopping ! I'll post the results here when I have put everything together.


PostPosted: Wed Oct 22, 2014 3:36 pm    Post subject: Reply with quote
Ellery wrote:
I'll consider it a 345mm and keep in mind the restricted fov


I would suggest considering it a 230mm – there is nothing magical about the 135 format that makes it sensible to convert all focal lengths to 135 equivalents. The crop factor is a made-up means to ease comparison between formats, and 135 is chosen as the reference simply because it happened to be the most familiar format to consumers in the film era, and because fixed-lens compact cameras have a myriad of different sensor sizes. Now it's increasingly anachronistic and a common cause for misunderstandings and confusion. Also, with interchangeable lens cameras you can use a lens with the same focal length (not converted to “equivalent”) to see what the angle of view looks like (e.g., if you have a zoom that goes to 300mm you can zoom it to 230mm and see what a 230mm would be like).

Anyhow, a 230mm is a 230mm, and once you learn what angle of view it gives on your camera, you don't need to think about the crop factor…

Last edited by Arkku on Thu Oct 23, 2014 12:33 pm; edited 1 time in total


PostPosted: Wed Oct 22, 2014 11:37 pm    Post subject: Reply with quote
Some good answers put more eloquently than I could have written.

I have a number of M42-M39 adapters, the small rings that allow you to put M39 lenses in an M42 mount. These are useful when making adapters. As are T mounts. Some old lenses have a removable ring allowing you to mount them on a lens board, adapt a home made lens board. If these lenses don't have a removeable ring, I would find a tube made from plastic to go over the thread on the lens. I use tubes made from aerosol caps, water pipe, medicine and vitamin bottles etc. Find one the right size and hot glue the lens on to it. finish it off with a half a yard of electricians tape. The other end can have the M42 adapter glued on.

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