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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

5k Scarlet and Epic are 1.2 Crop Cameras

Jason Ing said:
So what is the pros/cons of a full frame vs a "crop"? The angle of view changes and...?

And if I have a 24, 50, and 85mm, what do they become with a 1.3 crop?
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You have a 24, 50 & 85 exactly as written on them.
 
lol here we go again.
 
Andrew Walker said:
Well the angle of view is directly related to the crop factor on a lens.
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Lenses don't have crop factors, sensors do.

Michael is right, we should not be talking in "crop factors". And if you will notice, I didn't reference any. I've said this many times before in the past.

Since focal length is a fixed factor, as in a 50mm is a 50mm and always a 50mm, crop factors become an arbitrary relationship. Around here, most people who are thinking in "crop factors" are asking how a format relates to full frame 35mm photography. Or at least that is assumed. But in reality, as soon as someone asks "what is the crop factor" you have to ask "in relation to what?". Especially now with so many newer digital formats coming into play. And we have people asking what the crop factor is between Scarlet 2/3 and S35. For people who have been shooting S35 or APS-C and have never shot FF35, they don't have the same concerns about crop factor. Yet, many don't understand that if they put a FF35 lens on their S35 camera, the FOV will be the same as if they used a S35 lens of the same focal length.

Or maybe I'm thinking about field of view. Either way I would like to know how much of the Canon 24mm f1.4 II lens I'm going to be looking out of on Epic. From the design of the sensor it looks like the widest field of view might be 2:1. So I think all this talk about crop factors is very relevant to those that need a wide field of view for certain shots using FF35 glass.
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Your FOV with that Canon 24mm lens will be the same as if you have a 24mm Zeiss S35 speed, Ultra or Master prime on there. It will be the same as if you are using a 24mm Nikkor or whatever. Slightly wider than a 25mm RPP, but you would only know if you compared the same shot with the two lenses side by side. Focal length is focal length... Doesn't matter if it's FF35 or S35 glass. The only thing that changes is the COVERAGE provided by the lens in question. FF35 lenses are designed to cover full frame or a 43mm image circle. S35 lenses are designed to cover S35 and usually have about a 31mm image circle for full aperture S35. 5K on M-X is slightly larger, and needs a 32mm image circle of coverage.

Andrew, I'm not picking on you... You just got quoted. As JD said above, Here we go again!
 
Jason Ing said:
Really? Oh, I thought they changed. Like the 85mm becomes the equivalent of around 100mm, etc. Okay, good to know. Thanks!
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Stephen was referring to the fact that the focal length doesn't change. When moving a FF35 lens from an FF35 camera to a 1.6 crop camera like the 7D the field of view does become narrower.

Check out the graphic in this post: www.reduser.net/519532
 
Justin O'Neill said:
Stephen was referring to the fact that the focal length doesn't change. When moving a FF35 lens from an FF35 camera to a 1.6 crop camera like the 7D the field of view does become narrower.

Check out the graphic in this post: www.reduser.net/519532
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Ahh, that's what I was looking for. Thanks for the great graphic! That's some good info on that thread too.
 
So Jeff are you trying to say that they is no difference in the coverage of a Canon 24mm still lens and a 24mm Zeiss S35 speed. Because I'm willing to bet that if I put a 28mm Zeiss ZF lens on my 5D2 and then put it on my RED MX it will be much wider on the full frame 5D2. Just to be clear I'm not saying nor have I ever said that the crop factor changes your lens to a different focal length. I'm saying that your field of view is different.

I can already tell this is going to require pictures for comparison
 
Jeff Kilgroe said:
Lenses don't have crop factors, sensors do.

Michael is right, we should not be talking in "crop factors". And if you will notice, I didn't reference any. I've said this many times before in the past.
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The problem is there are way more still shooters in the world then there are folks shooting motion and still camera manufacturers are still adhering to the common crop factors: the 5D is full frame, the 1D mkIV 1.3 crop and the 7D 1.6 crop. Most stills shooters understand this system and are now experimenting with shooting video on their HDSLRs. When they start looking to move up and are looking at how a 5k Scarlet will work with their existing lens set we can't just tell them, "ignore the crop factor it doesn't apply to video". We tell them, ok, the 5k Scarlet is basically a 1.3 crop camera, but not exactly, because we shoot many different aspect ratios and a video frame is usually not as tall as a still frame.

This all ignores the bigger problem, however. Field of View is the aspect all shooters are interested in and there is no metric to describe it! Sure crop factor is confusing, but what is the simple, straight forward way of describing all this?
 
Andrew Walker said:
So Jeff are you trying to say that they is no difference in the coverage of a Canon 24mm still lens and a 24mm Zeiss S35 speed. Because I'm willing to bet that if I put a 28mm Zeiss ZF lens on my 5D2 and then put it on my RED MX it will be much wider on the full frame 5D2. Just to be clear I'm not saying nor have I ever said that the crop factor changes your lens to a different focal length. I'm saying that your field of view is different.
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No, not saying that at all. Definitely a difference in coverage. Coverage is what makes a lens suitable for FF35 and another of the same focal length only suitable for APS-C, for example.

If you take your 24mm FF35 lens it obviously covers FF35. It also covers S35 and smaller formats. Those smaller formats give a smaller / cropped FOV due to the smaller imager.

If you take a 24mm Zeiss S35 lens and put it on the S35 camera, it will give the same FOV as the 24mm FF35 lens does on the S35 camera. However, if you put that 24mm S35 lens on a FF35 camera, it will most likely vignette because it doesn't have the coverage.

I can already tell this is going to require pictures for comparison
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If I only had $5 for every picture I have already posted on this topic... Here's a couple:

ff35coverage.gif


ffs35compare.jpg
 
"Crop Factor" is a very simple shorthand for sensor size that most still shooters understand. Since Red has essentially taken DSLR sensor technology and developed a throughput for film frame rates, it's a very natural translation to Red. The numbers quoted here of 1.2 - 1.3 crop factor are quite helpful and intuitive for anyone who understands the difference between the two dominant DSLR sensor sizes.
 
Justin O'Neill said:
Field of View is the aspect all shooters are interested in and there is no metric to describe it! Sure crop factor is confusing, but what is the simple, straight forward way of describing all this?
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James and Justin I have to disagree - a great deal of still shooters don't understand it (some do) or we wouldn't be correcting people all of the time on this forum.

Angle of view is pretty simple and much more precise - and eliminates any confusion about crop factors from what to what (i.e. just in the RED world are we scarlet 2/3" crop factor vs the only other RED size - S35, or 2/3" to FF35.)

Isn't just better to say a 50mm is
about 50 degrees on FF35 (actually 46)
28 degrees on RED/4K S35
21 degrees on 3K
14 degrees on 2K

It isn't easy to remember right now but it is just as easy as remembering the different crop factors and much more precise than crop factors which are meaningless to anyone that doesn't have experience with FF35 SLRs - which isn't a problem for most of us oldtimers but certainly can be for those who grew up in the digital era.
 
Tom Lowe said:
As far as I know EF-S lenses (APS-C) will not even fit on EF-mount cameras. However, EF lenses will fit on EF-S.
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They fit, just don't work well. For instance I know the tokina works on the 5D at about 15-17mm

Jeff Kilgroe said:
I'm thinking most lenses will be OK, we may see some vignetting on wide focal lengths, especially on lenses like the 11-16 Tokina. The 5120 pixels wide is still a 1.89:1 aspect if recording the full 2700 pixel hight. That gives us a 31.26mm image circle.
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Is there any way we can figure out just how much coverage aps-c lenses give? I think Bloom said EFS won't work on APS-H...
 
At the risk of confusing things even further...

What is most helpful to me is what focal length gives me a "normal" field of view on a particular format. Normal defined as "similar to human vision sans peripheral" which used to be 50mm on still film cameras.

Obviously its important to know whether a particular optic will vignette or not. Past that, I just want to be able to pull the right lens for the shot I am visualizing the first time. Moreover, if I am budget limited on how many primes I can have, I want to choose the focal lengths I am most likely to need.

Anyone know where I can get a decent director's finder with tons of format selections for under $300? Until that question gets a lot of responses, these kind of threads are likely to continue.

BTW - That Duclos PL version of the Tokina 11-16mm is a tremendous lens.

Cheers - #19
 
Wouldn't the diagonal measurement of the sensor OR the different diagonal distance of the crops used on the sensor be the most important measurement? These are how I compare the different sensors myself.
 
Rick Burnett said:
Wouldn't the diagonal measurement of the sensor OR the different diagonal distance of the crops used on the sensor be the most important measurement? These are how I compare the different sensors myself.
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Comparisons of diagonal measurements only apply if the aspect ratios are the same. Knowing the diagonal measurements is good, that tells you the minimum diameter image circle you need to cover your sensor format. But you can't compare or figure a crop factor diagonally if between two differently proportioned formats.

A quick example of how diagonal measurements compared between two aspect ratios can fall apart would be something like this.

4:3 sensor 24x18mm, then the diagonal is 30mm.

2.3:1 sensor 27x12mm, the diagonal is also 30mm.
 
I meant towards the minimum diameter image circle in determining what lenses will work. In my mind though, when comparing two different aspect ratios, it's totally different to me because there is such a difference between H and V field of view, but if you rotate the camera diagonally to the diagonal, that part of the image will be identical on both sensors, however, since the H to V pitch difference at the angle of the diagonal will mean a different # of pixels if the same pitch is used.

That makes it much more clear doesn't it?? Hahaha. :)

I think all this just illustrates, it can be complicated to talk about. However, when I actually use these things and observe the output of different cameras, then it becomes much clearer.
 
"Crop factor" is just shorthand for the cropping that takes place down from FF35. IMO, it's very useful, since many people have experience on still cameras... and because I am convinced that the new Red FF35 Monstro will become the flagship camera and new standard for the motion industry.
 
I don't think there's anything wrong with using the term "crop factor" if it gives people a quick and dirty understanding of whether a lens on a given camera is going to be "wide", "neutral" or "tele".

Most people get that a 50mm lens on a still 35 mm film camera is about neutral, so anything below that is wide and anything above is tele.

That way, if I know that a camera has a crop factor of 1.2 for instance, that a 35mm lens is still going to be slightly wide.
 
Steve Dent said:
I don't think there's anything wrong with using the term "crop factor" if it gives people a quick and dirty understanding of whether a lens on a given camera is going to be "wide", "neutral" or "tele".

Most people get that a 50mm lens on a still 35 mm film camera is about neutral, so anything below that is wide and anything above is tele.

That way, if I know that a camera has a crop factor of 1.2 for instance, that a 35mm lens is still going to be slightly wide.
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This is EXACTLY how I work. I use a 30mm on a APS-C sized which is like a 50mm on a FF35 sized sensor. Anything above or below that I know will be tele or wide.

So with that, what does 50mm FoV on a FFF35 translate too on a 2/3 to be? (what focal length lens)
 
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