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Please help me choose 25mm lens for anamorphic shooting
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PostPosted: Tue Feb 07, 2017 12:39 am    Post subject: Please help me choose 25mm lens for anamorphic shooting Reply with quote

I own a Blackmagic micro cinema camera, and ISCO S8/2x Anamorphic attachment that I use to make videos.

Currently I'm finishing my first project, my setup looks like this: BMMCC (super 16 sensor), 28 2.8 C/Y Distagon, ISCO S8, SLR Magic Rangefinder.

The image that I get out of it is nice, I like how sharp Distagon is, but there are several things I think I can improve with choosing more suitable lens.

First – several times I have encountered situations when I could use quite a bit more light, and f2.8 is somewhat slow to be frank.

Second – I am cropping all my footage from 3.5 to 2.6 ratio, so a little vignetting would not be a problem, and I can go down to 25mm and get just a bit more of that precious vertical FOV.

Third – get a bit more "character". I'm not sure about this one, but I occasionally enjoy the swirly bokeh of Petzval-type lenses.

So I am looking at various 25mm lenses, C-mounts and other mounts from 16mm cameras, but also looking at Speedbooster+35mm lens options. I know speedboster can get you a +1 stop of light, and that's one of the main reasons why I want to change the lens.

So here are things I'm looking for:

1. As much light transmission as possible, for a reasonable price. I have seen 0.78 and 0.85 C-mount lens, but am not sure how much light will they let through, compared to more common and cheap f1.4 stuff.
2. Shallow DOF with a so-called "3D pop" effect. I am not sure how big the difference between 0.78 Canon, 0.85 Fujinon, 1.1 Switar and all the rest 1.4 lens would be. The sensor that I'm dealing with is pretty small, and getting shallow DOF is quite hard, so I will value the smallest differences. Also various lenses render volume differently, and I'd love to know your opinions about what you're using.
3. Sharpness wide open. I don't expect anything to be as sharp as the distagon, but would appreciate if it's close.
4. As small entrance pupil as possible – the rear element of the anamorphic attachment is around 30 mm, so anything less then that should work, preferable 20-25mm entrance pupil.
5. Front glass close to the edge of the lens barrel (not super deep inside like some cine lenses out there have) – so I can mount the anamorphic as close to the glass as possible.
6. Front threads of that will take common stepping rings.

I would appreciate any opinions or help, I have never owned any C-mount glass and would appreciate thought from those, who did.

Thanks!


PostPosted: Tue Feb 07, 2017 8:56 am    Post subject: Reply with quote

won't work, that ISCO S8/2x anamorphic adapter cannot handle a lens as wide as 25mm. Honestly one for 16mm or even 35mm film would work much better, like the famous ISCORAMA one (I have one laying around unsued which could be adapted and used, even with a better 1.75x factor needing less cropping).

PS: I do have the 0.78 and 0.85 C-mount lenses you talked about, in case you need them (Fuji resp. Canon)

How do you like that?






PostPosted: Tue Feb 07, 2017 11:59 am    Post subject: Reply with quote

kds315* wrote:
won't work, that ISCO S8/2x anamorphic adapter cannot handle a lens as wide as 25mm.


What do you mean? The 28mm shows almost no vignetting, so I'm assuming that 25mm will show very little, just enough for me to crop the sides and get around 2.6:1 ratio.

The second image that you've posted looks like it was shot wide open, what was it shot with?

Thanks for your help!


PostPosted: Tue Feb 07, 2017 7:18 pm    Post subject: Reply with quote

redimp wrote:
kds315* wrote:
won't work, that ISCO S8/2x anamorphic adapter cannot handle a lens as wide as 25mm.


What do you mean? The 28mm shows almost no vignetting, so I'm assuming that 25mm will show very little, just enough for me to crop the sides and get around 2.6:1 ratio.

The second image that you've posted looks like it was shot wide open, what was it shot with?

Thanks for your help!


Sorry, had overlooked that your Blackmagic micro cam only needs about 14mm image diameter, since it is a Super-16 format.

That explains, why you haven't gotten vignetting... Wink

Yep, that was shot wide open using an ISCORAMA 50mm f2.8