GrahamH
Well-known member
Dude I answered this already in my previous post. We do know how our lenses work. Some other people don't seem to.
GH2 crop factor 1.86x or 2x ?
- Thread starter Apefos Adapter
- Start date
Cosimo Bullo
Veteran
OP: Are you happy now?? Look what you've created!!! :cheesy:
Apefos Adapter
Well-known member
I am surprised. I did not imagine the thread would go on so much...
There is lot of information here, I think the question is answered.
I think people can stop talking now and go shoot...
thanks everybody
There is lot of information here, I think the question is answered.
I think people can stop talking now and go shoot...
thanks everybody
I didn't say a 50 isn't a 50 anymore. I clearly put FOV in there, which stands for field of view. And yes the mount makes a difference because lenses made for different purposes (cinema vs still) have different mounts and different size image circles. This is according to what others stated earlier in this thread and I simply was asking someone to throw both a still lens and a cinema lens on the GH2 and show the comparison. If they are in fact the same, then since we're talking about filmmaking here and not photography only the Super 35 crop factor should be used.
That's not what others have said in this thread. Others have said to use the full frame crop factor because the lenses are still lenses and are made for full frame use, whereas cinema lenses are made for Super 35 use. That would mean that they must have different sized image circle and therefore would crop differently. Again, we need someone to test this to compare the crop of the two different types of lenses.
Here's what I'm trying to determine.. if it works like this:
View attachment 45574
This example is not to scale. I just did it quickly in Pages.
In the example there are 2 different image circles of the same subject, one from a still lens and one from a cinema lens. The image circles are identical in what they show, but they are different size image circles. Depending on the sensor you project the image circle onto you will get a different final field of view. The full frame sensor will be filled by the still lenses, but will vignette with the cinema lens. The 4/3 sensor will be filled by both, but because the image circles are different sizes, you would see a larger final field of view with the cinema lens than the still lens.
This is what I want to test, to see if it works like this. I just don't have a PL adapter or a PL lens, otherwise I'd do it myself.
View attachment 45574
This example is not to scale. I just did it quickly in Pages.
In the example there are 2 different image circles of the same subject, one from a still lens and one from a cinema lens. The image circles are identical in what they show, but they are different size image circles. Depending on the sensor you project the image circle onto you will get a different final field of view. The full frame sensor will be filled by the still lenses, but will vignette with the cinema lens. The 4/3 sensor will be filled by both, but because the image circles are different sizes, you would see a larger final field of view with the cinema lens than the still lens.
This is what I want to test, to see if it works like this. I just don't have a PL adapter or a PL lens, otherwise I'd do it myself.
M. Gilden
Canon DSLR Moderator
No, I see what you are trying to say, but that's not how it works to my knowledge. In your chart, you show the cinema lens being smaller, but yielding the same FOV. In fact, the cinema lens is cropped, as it doesn't need to cover the same amount of space.
Much like a lens made for 16mm film used on a full frame sensor won't cover the entire thing (resulting in a vignette), however the part that IS visible will be the same as a full frame lens of the same focal distance.
In other words, a full frame 50mm will show the mountain and landscape, etc, at a certain size. A cinema lens or 16mm lens or any other smaller size lens doesn't need to cover as large of a sensor, so it will be cropped inward. If the inward crop is more than the size of your sensor, you will lose definition on the borders. But the magnification in the center is always the same.
Does that make more sense now?
You don't need a PL mount to test this- if you've got a GH2, try some C-mount or 16mm glass. A C-mount lens won't cover the entire sensor, so you'll end up with only a clearly visible center. But that visible center at 28mm will be the same as what is visible on a M4/3rds mount lens at 28mm. Which, in turn, will be the same as a full frame vintage lens at 28mm. The difference between using a full frame lens and a cinema lens is only noticeable if shooting with a sensor larger than the image circle (like when using a full frame camera). The center of the image stays the same, and when using cropped sensors as small as the GH2, almost any glass is usable.
Therefore, as we said earlier, a 50mm FOV is the same no matter what type of lens.
Last edited:
Thank you for clarifying. This was what I originally thought, but was confused by some of the other things being said and so wanted to be sure what was correct. So therefore, since the center image is the same, when shooting video with the GH2, we should in fact be using the Super 35 frame size as the standard reference for crop factor, since that is what is the standard in filmmaking. Photography and stills shooting is a whole different thing. So crop factor on the GH2 is only 1.3x.
M. Gilden
Canon DSLR Moderator
Funny, I see it the other way around. If cinema lenses actually produced a different FOV, then it would make sense to change our reference to match that.
However, I just said that they ARE the same thing, since every lens will have the same magnification no matter what. However, your FOV is determined by the size of your sensor (or film), and unless you already have a background in cinema lenses, I don't see why Full Frame doesn't make more sense.
I think yoclay put it better than I could have:
I respect Barry Green's opinion very much. However at the risk of disagreeing with him, I don't think APS-C is the "new" we should be embracing. s35 is the old- it is the limited size of film we used to have, there weren't other options without it becoming very expensive (IMAX) or very limited in FOV (s16mm). These days we have options, from the very small chip camcorders, to the "full frame" 1Dx and 5D, and various sizes in between. Since the world of photography has been bleeding into this one (heck, we're here discussing using DSLR PHOTOGRAPHY cameras for VIDEO!), and are often using lenses and bodies designed with full frame 35mm stills as a reference, doesn't it make sense to make that the universal language we are referring to?
To quote Barry's own words:
A crop factor is exactly as the name implies -- if you are using a sensor that is smaller than the referenced sensor, you can use a mathematical factor to determine how the angle of view will compare. So a 50mm lens on a full frame sensor gives an angle of view; the same lens on a sensor that is smaller -- 'cropped' -- will give a different angle of view. A narrower angle of view, as if the image was cropped ...
So there is only the relationship between the focal length and the sensor size. A 50mm lens on a Full Frame will always give the same angle of view; on an APS-C it will always give an angle of view based on the fact that the APS-C sensor is a cropped version of a Full Frame sensor. In fact, you could take the full frame image AND CROP IT to get the same result, hence the naming convention.
A lens that fails to cover the full sensor will vignette, but the angle of view will still be calculated based on the focal length and the sensor size -- the mount, the brand, the intent of the lens is irrelevant. It may not 'work' ... but if it does, the angle of view is exactly the same for every (for example) 50mm lens on any APS-C sensor, regardless of the mount or design.
There is nothing new in any of this -- years ago I worked as a photographer -- and 'full frame' 35mm was the junior format to 60mm square. Same deal -- there was a crop factor (though I never heard the term used) so a 50mm lens was a wide angle on a Hasselblad. Note too that we had different aspect ratios too; 6x6 or 6x7 or 6x4.5 ... the last of which matched the shooting frame of 35mm in terms of ratio but obviously not area. And the standards for prints were none of those -- 3 1/2 x5, 8x10 and 11x14 typical sizes, none of them matching the shooting ratios.
So there is nothing to test -- the science is absolute. And the importance is entirely personal -- if for some reason you can only imagine something in 35mm Full Frame terms, then a crop factor will let you do a quick comparison. For that matter, you could calculate a crop factor compared to some other format -- compared to Super 8, for instance, if that was your thing. Or to a 6cm square Hasselblad, if that was your norm. But it is not as complicated as this thread seems to imagine, and there is no testing or proving that needs to happen -- the math is simple, repeatable and absolute ... if you want to use Full Frame 35mm as the baseline, you can calculate once the APS-C crop factor and apply it to every lens ever made.
Cheers,
GB
So there is only the relationship between the focal length and the sensor size. A 50mm lens on a Full Frame will always give the same angle of view; on an APS-C it will always give an angle of view based on the fact that the APS-C sensor is a cropped version of a Full Frame sensor. In fact, you could take the full frame image AND CROP IT to get the same result, hence the naming convention.
A lens that fails to cover the full sensor will vignette, but the angle of view will still be calculated based on the focal length and the sensor size -- the mount, the brand, the intent of the lens is irrelevant. It may not 'work' ... but if it does, the angle of view is exactly the same for every (for example) 50mm lens on any APS-C sensor, regardless of the mount or design.
There is nothing new in any of this -- years ago I worked as a photographer -- and 'full frame' 35mm was the junior format to 60mm square. Same deal -- there was a crop factor (though I never heard the term used) so a 50mm lens was a wide angle on a Hasselblad. Note too that we had different aspect ratios too; 6x6 or 6x7 or 6x4.5 ... the last of which matched the shooting frame of 35mm in terms of ratio but obviously not area. And the standards for prints were none of those -- 3 1/2 x5, 8x10 and 11x14 typical sizes, none of them matching the shooting ratios.
So there is nothing to test -- the science is absolute. And the importance is entirely personal -- if for some reason you can only imagine something in 35mm Full Frame terms, then a crop factor will let you do a quick comparison. For that matter, you could calculate a crop factor compared to some other format -- compared to Super 8, for instance, if that was your thing. Or to a 6cm square Hasselblad, if that was your norm. But it is not as complicated as this thread seems to imagine, and there is no testing or proving that needs to happen -- the math is simple, repeatable and absolute ... if you want to use Full Frame 35mm as the baseline, you can calculate once the APS-C crop factor and apply it to every lens ever made.
Cheers,
GB
Because 35mm Full Frame is a Still Photo frame of reference that has nothing to do with film or video cinematography, so why would you use a still photography frame of reference ?
As I've stated before, I've shot still photos with a wide variety of camera formats... Right up to the 20x24 inch Polaroid format.
The 35mm Full Frame Still Photo format has a crop factor of 6.6 when compared to the 8x10 inch film format, but I would never use the 8x10 inch film format as my point of reference, just like I would never use the 35mm Full Frame Still Photo format as my frame of reference. It just makes no sense at all.
Since modern large sensor video formats are based upon the 35mm Motion Picture film formats, the most useful frame of reference are the 35mm Motion Picture formats. If I am not familiar with this format, then I need to educate myself to properly understand the format, rather than try an retro-fit everything to my previous experience with the 35mm Full Frame Still Photo format because I am not prepared to learn the cinematographic standards.
To me is smacks of laziness and lack of mental agility if you are not prepared to learn and understand the cinematographic standards that large sensor video is based upon.
Because this isn't photography. It doesn't matter what your background is. You've entered the world of cinematography. Any professional cinematographer is going to think in terms of cinematography, not photography, and the standard for cinematography is Super 35, not Full Frame.
No, because you'd be asking the entire world of cinematography to change just because some people want to shoot movies with a DSLR. Now if all the cameras started coming out with Full Frame sensors, then you could have an argument here. But there's very few cameras with Full Frame sensors being used for shooting movies and they are all DSLR cameras. All the real professional cameras used to shoot movies are generally built around an S35 sensor. So you would use the S35 standard. I really don't see how a bunch of photographers can jump into the cinematography world and ask cinematographers to change to Full Frame thinking because there's a few Full Frame cameras being used to shoot video. What it should be is if you're using a Full Frame sensor you think with a crop factor of 0.7x (a 50mm would be a 35mm FOV in cinematography terms). This way the cinematographers (the majority in the field of cinematography) don't have to change.
As a cinematographer, if I jumped into photography I would not ask the photography world to suddenly adopt the cinematography world's way of thinking about frame sizes and FOV.
Let me put it another way... if you visit another country, do you demand that they speak to you in your native language? Probably not. When someone visits your country, would you expect them to speak your language (or at least try) or do you think they would demand you to speak their language? Probably not.
Last edited:
Totally agree.
M. Gilden
Canon DSLR Moderator
Whoa there- I'm not asking the world of cinematography to change anything!
This isn't even the cinematography section of the forum. This the Panasonic GH2 section. The Panasonic micro 4/3rds STILL CAMERA that happens to be an excellent tool for low budget cinema. I'm talking about only HERE, in reference to discussing the crop size of using DSLR for video, referring to full frame when discussing the FOV makes sense. Everyone is obviously welcome to refer to it however they want, and if using cinema lenses even more so the right to disagree. But some folks here seem to take it personally when crop sizes of these DSLRs are compared to full frame, despite the fact that this is a photography camera, most likely using photography lenses. I am merely explaining why many of us do it, and why many more will likely continue to. The lines between photography and videography are blurring- I know more than just a few of us have pulled double-duty with these cameras.
If I implied that the entire world of cinematography was at stake, I apologize.
This isn't even the cinematography section of the forum. This the Panasonic GH2 section. The Panasonic micro 4/3rds STILL CAMERA that happens to be an excellent tool for low budget cinema. I'm talking about only HERE, in reference to discussing the crop size of using DSLR for video, referring to full frame when discussing the FOV makes sense. Everyone is obviously welcome to refer to it however they want, and if using cinema lenses even more so the right to disagree. But some folks here seem to take it personally when crop sizes of these DSLRs are compared to full frame, despite the fact that this is a photography camera, most likely using photography lenses. I am merely explaining why many of us do it, and why many more will likely continue to. The lines between photography and videography are blurring- I know more than just a few of us have pulled double-duty with these cameras.
If I implied that the entire world of cinematography was at stake, I apologize.
This is primarily a filmmaking website. I'd venture to guess that 99.9% of the posts are filmmaking and cinematography related. See that DVXuser logo in the open left corner of the page? It says "The Online Community for Filmmaking". So to come here and say to use the Full Frame sensor crop factor is saying that cinematographers need change the way they think. This is a filmmaking and cinematography world here. Super 35 is the standard, not Full Frame.
The AF100 is based on the GH1. The AF100 is a video camera. The GH1 and GH2 are DSLRs. They have the same size sensor. Are you saying the GH1 and GH2 should have a crop factor based on Full Frame, but the AF100 based on S35 (because it's not a DSLR)? That wouldn't make sense. Whatever the tool is you're using to shoot a movie, the crop factor should be referenced in terms of S35.
I'd even venture to say more GH2's were bought for the primary purpose of shooting video than for photography. I think any real serious photographer (with no interest in shooting video with it) would buy a Canon or Nikon before a Panasonic.
Last edited:
Ian-T
Veteran
Shooter
Veteran
Crop Factor ...schmock factor...schlock factor.....
Here is the way I and my colleagues (crew) saw it.... the moment we got involved in MFT sensors in regard to crop factors.
It is what it bloody is!
Nothing more ...nothing less. It is what the result is to the eye.
Put a lens (any lens) on the camera..thats what you get. (Deal with it)
What exactly do you do with the crop factor information even when you know what it is?
Here is the way I and my colleagues (crew) saw it.... the moment we got involved in MFT sensors in regard to crop factors.
It is what it bloody is!
Nothing more ...nothing less. It is what the result is to the eye.
Put a lens (any lens) on the camera..thats what you get. (Deal with it)
What exactly do you do with the crop factor information even when you know what it is?