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Wide very old vs new
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PostPosted: Fri Sep 09, 2011 3:09 pm    Post subject: Wide very old vs new Reply with quote
A quite old wide vs a relatively new lens - opinions?









a very unfair comparison for various reasons, butI just wanted your opinions on the results first.

.


PostPosted: Fri Sep 09, 2011 3:17 pm    Post subject: Reply with quote
The images on the right show an obvious distortion, that is absent from the left side images, but there's also to say that the image circle in the right side images is narrower (you can see vignetting on corners). So probably part of the distortion would not appear so dramatic when the lens is used with the original camera format.
Regarding the enlargements, the images on the right appear oversharpened compared to those on the left. It's difficult to say anything more on the image quality without looking at the full size images.


PostPosted: Fri Sep 09, 2011 3:19 pm    Post subject: Reply with quote
I agree with Orio; the oversharpening makes a fair comparison difficult. Interesting question though!


PostPosted: Fri Sep 09, 2011 3:26 pm    Post subject: Reply with quote
All images were processed identically within the same batch. The right ones are simply very sharp already as original (Zeiss Tevidon 1.4/25mm at f11), but admittedly the image circle barely matches the camera sensor (Lumix GH2). I was just astonished that this quite old unlabeled wide angle (approx. f=20mm, f11 fixed aperture) holds up quite well against it (covers approx. 120 x 120mm film format)


PostPosted: Fri Sep 09, 2011 4:27 pm    Post subject: Reply with quote
Quite difference in sharpness! The coatings on right lens are better, for more contrast, deeper colors.


PostPosted: Fri Sep 09, 2011 4:30 pm    Post subject: Reply with quote
Yes indeed, the old one has either none or a barely visible single coating


PostPosted: Fri Sep 09, 2011 5:02 pm    Post subject: Reply with quote
Can I get a lens with the colors and contrast from the right and the detail from the left? I'm curious about the last pairing -- the gate. Why does the lens on the left provide a uniform look to the gate mesh while the lens on the right cause it to look like a poor-man's optical illusion? The left image must be truer to life.


PostPosted: Fri Sep 09, 2011 6:27 pm    Post subject: Reply with quote
The left one came from a military aerial imaging system (an educated guess) with nearly zero distortion (few microns allowed only) and absolutely flat field over a very large image area, so very well spotted David! Good eye you have indeed. High contrast is not everything, but that "gets people"... Wink

P.S.: Oh yes, I could get you a lens that does both, but are you prepared to spend $$.$$$ for it?


PostPosted: Fri Sep 09, 2011 8:31 pm    Post subject: Reply with quote
The original price of a flat-field 20mm with 5x5" coverage will doubtlessly have been at least a hundred times above the price of a humble Tevidon - that must be among the widest lenses ever...


PostPosted: Fri Sep 09, 2011 8:37 pm    Post subject: Reply with quote
The widest I ever heard of Sevo indeed - made for the military, so who cares (cared actually) about cost Wink Wink


PostPosted: Fri Sep 09, 2011 9:14 pm    Post subject: Reply with quote
You should try it out on a medium format camera. Must be similarly wide, as the 12mm f5.6 Voigtlaender.


PostPosted: Fri Sep 09, 2011 9:15 pm    Post subject: Reply with quote
Much more, approx coverage 120 x 120mm


PostPosted: Fri Sep 09, 2011 9:21 pm    Post subject: Reply with quote
kds315* wrote:
Much more, approx coverage 120 x 120mm
Hoppla, I read 5x5 cm instead of inches. Can it go wider than 180°? Time to pick up large-format photography.


PostPosted: Fri Sep 09, 2011 9:29 pm    Post subject: Reply with quote
I estimate it to cover around 100 degrees


PostPosted: Fri Sep 09, 2011 9:34 pm    Post subject: Reply with quote
Apparently the 12mm covers 121°, while a 20mm covers 94° horizontally on 135 film.

120/35~3.4 factor

94x3.4=too much. Laughing

But I suspect my photographic theory on imaging angles to be completely wrong.

Last edited by Cistron on Fri Sep 09, 2011 9:39 pm; edited 1 time in total


PostPosted: Fri Sep 09, 2011 9:38 pm    Post subject: Reply with quote
Yes, I agree Wink


PostPosted: Fri Sep 09, 2011 9:47 pm    Post subject: Reply with quote
kds315* wrote:
Yes, I agree Wink
Hehe. Ok, I quickly browsed Wikipedia on how to calculate angles of view. Their formula is

angle = 2 * arctan(dimension/2*focal length)

That gives 2.5 rad, or ~140° - neat!


PostPosted: Fri Sep 09, 2011 9:52 pm    Post subject: Reply with quote
Put this on your 4x5 field camera - wait, you would probably need a special camera ! I don't think many 4x5's will take the tiny back focus of this thing.

How did you mount this thing on your Lumix ?

Or more fundamentally, what does this thing look like ?

You would be a celebrity among the large format people.


PostPosted: Fri Sep 09, 2011 10:04 pm    Post subject: Reply with quote
Cistron wrote:
kds315* wrote:
Yes, I agree Wink
Hehe. Ok, I quickly browsed Wikipedia on how to calculate angles of view. Their formula is

angle = 2 * arctan(dimension/2*focal length)

That gives 2.5 rad, or ~140° - neat!


Yes, I know that formula, hence my comment Wink


PostPosted: Fri Sep 09, 2011 10:04 pm    Post subject: Reply with quote
luisalegria wrote:
Put this on your 4x5 field camera - wait, you would probably need a special camera ! I don't think many 4x5's will take the tiny back focus of this thing.

How did you mount this thing on your Lumix ?

Or more fundamentally, what does this thing look like ?

You would be a celebrity among the large format people.


Nah, I only use it for my "exotic stuff" as it neatly transmits UV also...
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