Chronos > Chronos User Discussion

Let's talk LENSES!

<< < (2/8) > >>

Electra:
My collection is the 2/3"  12mm, F/1,6 Prime that David offered with the kickstarter. (This will be the lens that will stay on the camera when it's packed away.)
* A Secondhand Cosmicar 22-66mm, F/1.8 Zoom 'TV Lens' that should be at least full 2/3" or better frame.
* AU$75 8-50mm F1.4  1/2"  Lens from Aliexpress that is our 'cheap lens' test.
* And currently at a friend's place but promised to me, a "Zenit Photosniper" with a Tair-3AS 300mm f/4.5 lens that I have no idea what it'll be like to use but at least in full sunlight looks like it might work up to about 4000fps.

In 2-3 weeks I should have test footage with the first three up. The last one, I have no idea when I'll actually get it.  I'll update when I have info.
I'm very interested in what other's experiences are too.

akeeh:
My collection of C-mount lenses is as follows, I will post some test results with these (normal use and macro use with extension tubes) after I finally receive my camera, hopefully in the next coming weeks:
- VT Lens 12.5mm f/1.3
- Canon TV Lens VF 25mm f/1.4
- Tamron 25mm f/1.6
- Canon TV Lens PHF 35mm f/1.2
- VT TV Lens 50mm f/1.3
- Canon TV Lens VF 50mm f/1.8
- Two somewhat identical lenses with different manufacturer engraving: VT TV Lens 75mm f/1.3 and eneo TV Lens 75mm f/1.3
- Collection of extensions tubes and a 2x extender for C-mount
- Different microscope lenses and a C-mount adapter for them

I also have a Nikon F to C-mount adapter and I'll do more tests at least with these Nikon lenses: 35mm f/2.0D, 50mm f/1.4D, 55mm f/2.8 macro and a 180mm f/2.8

Dan Kanes:

--- Quote from: ExaltedDuck on July 15, 2017, 10:46:53 AM --- (a 50mm focal length lens for 16mm film frame should produce an image like a 58mm focal length lens on a 2/3" sensor).  Super-16 is pretty reasonable as well (a 50mm would behave like a 66mm).  Some good info is here and here.  I've been trying to think about the physics of it and while I think I kind of understand how the mismatch alters the field depth to behave like a different f-stop, I am inclined to believe this wouldn't have much impact on the light gathering performance. (if a 4/3" 50 mm f/2 lens is on a 2/3" sensor, we can expect it produce an image framed like 100 mm lens with the field depth of an f/4 aperture but I *think* it would provide the same contrast and brightness as though it were still on a 4/3" sensor at f/2. If anyone knows better, please, by all means, correct me. :) )

--- End quote ---

A lens's focal length is a different way of describing its Magnification effect.

A 50mm lens made for a 35mm camera will offer the same field of view as a 50mm lens made for 2/3" or 16mm.l [FOR A GIVEN SENSOR SIZE]

The angle of view is sensor dependent.

There are other factors that affect usability / quality of image - such as vignetting if the elements or element holders are not appropriatelt sized for the format.

This should help you understand :

http://blog.abelcine.com/2010/05/14/a-lens-is-a-lens-is-a-lens/


https://youtu.be/ZF4GSMw1CeQ

Personally I'm interested in applying a Focal Reducer to the Chronos to see what we can get out of it.

BiduleOhm:

--- Quote from: Dan Kanes on July 20, 2017, 04:44:23 PM ---A 50mm lens made for a 35mm camera will offer the same field of view as a 50mm lens made for 2/3" or 16mm.

--- End quote ---

Actually, no, the "A lens is a lens is a lens, and it doesn’t know what size sensor or film gate is placed behind it." is exactly why we have the crop factor. Please see https://photographylife.com/what-is-crop-factor and https://www.bhphotovideo.com/explora/photography/tips-and-solutions/understanding-crop-factor and https://en.wikipedia.org/wiki/Crop_factor

This means that for our 2/3" sensor the crop factor is almost 4, so a 50 mm lens on 2/3" sensor will have the same effect as a 200 mm lens on a 35 mm sensor, and what ExaltedDuck said is spot on (except the reference sensor isn't 4/3" but 35 mm).

John Delonghi:
A good focal reducer would make a lot of sense for the Chronos. Especially if, like me, you've got some decent 35mm glass and want to use it instead of investing in C mount lenses.

Has anyone tried one yet?

Navigation

[0] Message Index

[#] Next page

[*] Previous page