Super35 lenses on Super16!

[Giles]

Hey all,
What are the issues with using s35 lenses to shoot super16 (film)?

Specifically I have a set of Schneider Cine Xenar iii which I'm planning to but on an Arriflex SR3 or similar. I'm assuming that the excess coverage might result in more flaring? Are there any sharpness issues?

[morgan_moore]

Speaking from theory.

A capture media requires a lens that outresolves it to provide best sharpness.

Typically small capture media (eg 2/3 chip cams) require lenses that have a high (LPI) lines per inch making large sensor optimised lenses innappropriate on occasion.

Film is an 'oddity' in that a smaller capture area implies a smaller resolution (given a consistent stock)

And therefore any lenses optimised for that stock are good enough irrelevant of thier image circle.

ie.. they should be fine excluding flare risk and maybe you dont have enough FOV you might want an 8 or a 6 to shoot 16 master shots?

A proper matte box may help flare. Matte is a specific thing. Many people use matte boxes with no mattes in place.

[Giles]

Thanks, that makes sense! I would have assumed the same before reading this which cast some doubt: https://www.rogerdeakins.com/camera/...er-35-sensors/

On the same thread you could imagine some similar sharpness issues using s35 on s16, or something more pronounced... But the difference mr Deakins is talking about can't be massive, we've all done it that way round! And pin sharpness is not always what we're looking for

[morgan_moore]

Nothing seems to compromise what I said.

They are talking aobut video cameras which would indeed need more LPI from the lens on a smaller sensor.

They do not cross the 'oddity' of smaller film gate having a proportionally smaller resolution, assuming a consistent stock.

If you put 16mm on a 30foot screen you will see the grain before you see the lens anomolies. The anomolies were there but you didnt see them 'cos of the grain.

[Giles]

Ok gotcha. Thanks very much!

[Mitch Gross]

Speaking from both theory and hard-fought practical knowledge.

It's fine. Every S-35 lens and certainly the Cine-Xenar III series have very high resolving power at the lens center and throughout the S-16 image area. They are more than up to the task of resolving fully on a S-16 frame. As far as flaring goes, while the lenses do project well outside of the film gate the inside of the SR-3 is well flocked and darkened, and there's nothing that will create unwanted flare back onto the film. These lenses are in fact quite telecentric, so it is pretty much impossible for something like light bouncing off the groundglass and onto the negative.

There is one possible issue and you'll know it at checkout. The lenses are a bit fat and they are cylinder-shaped as opposed to many older lenses that are more cone-shaped. This can mean that it is possible that the rear of the lens and the viewfinder might get in each other's way and you won't be able to physically mount the lens. I don't think this is the case with the Cine-Xenar III series but I haven't tested.

[cyvideo]

On the same thread you could imagine some similar sharpness issues using s35 on s16, or something more pronounced... But the difference mr Deakins is talking about can't be massive

The difference can be quite noticeable. When using larger format lenses on smaller sensors you do tend to have the benefit of using the sweeter center of the lens due to the crop factor but you do lose resolving power and have no improvement in MTF. On the other hand, using a larger format lens via an optical relay group to a smaller sensor you can and generally will see benefits in certain areas. Namely a resolution boost, a reduction in aberrations, and a boost in exposure, and importantly MTF. What you are actually doing is converting a large format lens optically into a smaller format lens when using an optical relay group. Most of us would be familiar with the Metabones Speedbooster and its performance boost in the areas I mentioned. Look at the following image as an example of how this can be demonstrated quite clearly in the case of a FF lens on M43. To a greater degree or less, the optical physics at play here will apply to any larger format lens being used on a smaller format sensor given that the quality of the relay lens group used is of sufficient quality. So if I was using S35 glass on an S16 sensor and wanted the maximum in resolution, exposure value and field of view coverage I would be using a Speedbooster.

Chris Young

https://www.dpreview.com/articles/55...ro-four-thirds

FF Speedbooster M43.jpg

[morgan_moore]

He is talking about film - the plrastic rolls covered in chemicals.

A smaller film area doesnt need better lenses or speedboosting assuming that the lenses are good enough for the large format in the first place

OF course speedboosting is an option and may deliver different DOF and FOV but that is a different chat .. esp ase there is no PL ro PL booster ??

[cyvideo]

He is talking about film - the plrastic rolls covered in chemicals.

Well I'll be! I missed the plastic and emulsion point. Sloppy reading on my part! I guess some people still shoot film.

I have an ARRI 16ST, my ex Beeb one when they sold them off, and three DR 70s sitting around here as ornaments. Guess I'll not be buying any film soon so ornaments they remain. Sad in a way.

Chris Young

[Mitch Gross]

Not talking about using a speed booster here, and in fact such a thing is physically not possible witht he cameras in question. This is simply the question of using a S35 format lens on a S-16 format camera.

[Bruce Watson]

What are the issues with using s35 lenses to shoot super16 (film)?

I don't know what all of the issues are. But certainly one of them is the larger image circle that lights up the inside of the camera. That is, it lights up the inside of the camera around the smaller-than-designed-for sensor area. This happens quite a bit since the lenses (even those matched to the sensor size) have a round image circle while the sensors are rectangular. So a lot of light "falls off the edge" as it were. Most cameras do a good job of minimizing reflections caused by this.

My worry is that the "lit area" around the sensor area in your case will be very large. So any shot that includes a light source (think shooting into the sun) will probably cause an unreasonable amount of flare and reduced contrast. If you can keep light sources out of the frame you will probably be OK. But remember that the sky can be a huge light source.

Specifically I have a set of Schneider Cine Xenar iii which I'm planning to but on an Arriflex SR3 or similar. I'm assuming that the excess coverage might result in more flaring? Are there any sharpness issues?

There really shouldn't be much in the way of sharpness issues. The reason for this is that you are only using the center of the image circle. This is a bit like using the lens stopped down, probably near its optimal aperture. It should be about as sharp as it can get. This will also serve to minimize aberrations.

So.... give it a try. Shoot a roll, get it processed, project it, see what you think. If it works, it works. If not, plan B.

[Mitch Gross]

I don't know what all of the issues are. But certainly one of them is the larger image circle that lights up the inside of the camera. That is, it lights up the inside of the camera around the smaller-than-designed-for sensor area. This happens quite a bit since the lenses (even those matched to the sensor size) have a round image circle while the sensors are rectangular. So a lot of light "falls off the edge" as it were. Most cameras do a good job of minimizing reflections caused by this.

My worry is that the "lit area" around the sensor area in your case will be very large. So any shot that includes a light source (think shooting into the sun) will probably cause an unreasonable amount of flare and reduced contrast. If you can keep light sources out of the frame you will probably be OK. But remember that the sky can be a huge light source.

In practice a non-issue. I owned a S-16 camera for years. I had two Nikon still lens adapters, one with a narrow rear opening and the inside painted matte black and the other without. I used a variety of Full Frame Nikon lenses with these adapters and never could see any difference.