GH2 crop factor 1.86x or 2x ?

[Apefos Adapter]

And just to be über-pedantic, we need to specify we talking about equivalent to the FOV of a 100mm. Some folk talk about "equivalents" in discussions of depth of field, which is different again.

the depth of field is a different feature. It changes relative to sensor size. to find the shallow dof equivalent betwenn to different sensor sizes you can use this rule

for example: 35mm still and GH2, crop factor 2

35mm still fstop = 2.8
so wich will be the fstop to use in GH2 to get same shallow dof

the rule: divide the fstop from the bigger sensor by the crop factor

so 2.8 / 2 = 1.4

so you must use 1.4 in GH2 to get same shallow dof when using 2.8 in 35mm still

 

[Apefos Adapter]

Why to consider 35mm still when calculating FOV AOV Focal Lenght and so on

Because all vintage manual focus lenses was designed to 35mm STILL so it is important to know the real crop factor between GH2 and 35mm still

this will make more sense to calculate the equivalent to 35mm still when using an old photo lens in the GH2

 

[David W. Jones]

Unless you are shooting with a full frame 35mm camera like the 5DmkII, it makes absolutely no sense to compare your lenses to the FF35mm equivalent. Honestly, what do you care what a 50mm lens looks like on a full frame 35mm camera unless you are shooting with one? Those of us who have been shooting cine 35mm film for years already know what a 50mm lens looks like on a S35mm/APS-C sensor camera. Why would we need to compare it to a full frame still format?

 

[Apefos Adapter]

the depth of field is a different feature. It changes relative to sensor size. to find the shallow dof equivalent betwenn to different sensor sizes you can use this rule

for example: 35mm still and GH2, crop factor 2

35mm still fstop = 2.8
so wich will be the fstop to use in GH2 to get same shallow dof

the rule: divide the fstop from the bigger sensor by the crop factor

so 2.8 / 2 = 1.4

so you must use 1.4 in GH2 to get same shallow dof when using 2.8 in 35mm still

For example:

a 24mm lens with f3.2 in a 35mm still camera

will produce the same image (with same shallow dof) of the

slr magic 12mm f1.6 in Gh2

other example

a 100mm lens in 35mm still camera in f2.8

will produce the same image (same shallow dof) of

50mm f1.4 in GH2

 

[David W. Jones]

Why to consider 35mm still when calculating FOV AOV Focal Lenght and so on

Because all vintage manual focus lenses was designed to 35mm STILL so it is important to know the real crop factor between GH2 and 35mm still

this will make more sense to calculate the equivalent to 35mm still when using an old photo lens in the GH2

The image circle a lens will project has nothing to do with the "crop factor" of a sensor.

 

[Apefos Adapter]

Unless you are shooting with a full frame 35mm camera like the 5DmkII, it makes absolutely no sense to compare your lenses to the FF35mm equivalent. Honestly, what do you care what a 50mm lens looks like on a full frame 35mm camera unless you are shooting with one? Those of us who have been shooting cine 35mm film for years already know what a 50mm lens looks like on a S35mm/APS-C sensor camera. Why would we need to compare it to a full frame still format?

You must compare to the format you are familiar with

who comes from cinema must compare to cine and use crop factor from cine

I have never shoot anything wit a 35mm cine camera, so i am not familiar to it

But I used to be a photographer, i am very familiar to the old film cameras like nikon FM and Canon A1 so my mind always think considering 35mm still
So compare GH2 to Still photo cameras are very important to me to understand what i will get with each lens and each fstop

 

[Barry_Green]

a 50mm lens will always be 50mm in all cameras, but what changes it the EQUIVALENT do 35mm STILL. In GH2 a 50mm lens is EQUIVALENT to a 100mm in full frame STILL

Only in terms of field of view. Not in terms of DOF (at the same aperture). And if you back up to make it "equivalent" you change the perspective rendering. So while it's easy offhand "rule of thumb" to say it's "equivalent", the cold hard facts are: it isn't.

A lens doesn't know what sensor it's projecting its image onto. It projects the same image regardless. It's the sensor that does the cropping. When you realize that all 50mm lenses are performing the same at projecting that image, it makes the whole crop factor a whole lot easier to understand.

 

[Barry_Green]

For example:

a 24mm lens with f3.2 in a 35mm still camera

will produce the same image (with same shallow dof) of the

slr magic 12mm f1.6 in Gh2

other example

a 100mm lens in 35mm still camera in f2.8

will produce the same image (same shallow dof) of

50mm f1.4 in GH2

Yes, this is all correct -- if you equalize out the f-stop difference for DOF, you will get identical imagery by using that focal length difference, presuming that the camera is kept in the same place for both shots.

 

[M. Gilden]

a 50mm lens will always be 50mm in all cameras, but what changes it the EQUIVALENT do 35mm STILL. In GH2 a 50mm lens is EQUIVALENT to a 100mm in full frame STILL

Exactly, and in order for us all to understand what those numbers mean, we need to all be discussing the same reference system. 35mm film is still the standard in lens discussion and crop equivalents.

Like I said, a 50mm lens is always a 50mm lens, it doesn't matter what camera you mount it to. It is always a 50mm lens! The field of view from said lens will be determined by the sensor size but the lens does not magically become a 100mm when mounted to a M4/3 camera.

No one implied that it was, did they?

Well, then I'd say you should go to the photography forums and discuss crop factor with full frame sensors there. The vast majority (meaning nearly all) discussion here is regarding shooting video, so therefore we should be talking about crop factor when shooting video and comparing to S35 not FF35.

I don't think anyone is disputing the 1.9x 2.0x or 2.1x (or whatever it is) crop factor when comparing to the 5D or any other full frame-sized sensor. But really that crop factor has no bearing when you shoot with video because full frame is not the standard for shooting movies, Super 35 is. I really don't understand why no one gets this.

And what I don't understand is why you don't think this will confuse people even further.
Goodness, I do hate it when someone on the other side of the world says its 40 degrees outside. 40 degrees of WHAT?! That could be either quite cold or rather hot, depending on whether they are counting in Fahrenheit or Celsius. Understanding crop and FOV equivalents need to be on the same scale when discussing lenses, otherwise you are asking for a whole lot of confusion. Since everyone discusses these lenses and cameras (of all shapes and sized) in regard to 35mm full frames, it makes a lot of sense to continue discussing it that way- on any forum.

Additionally, how many of us are coming from a background in shooting with s35? I'm sure that there are more than a few, but even before the DSLR craze I recall seeing them refer to lenses on 16mm and 35mm using the full frame 35mm FOV equivalents. Many more of us have backgrounds in digital video, and using still photography as our reference for lenses. I know what a 28mm 50mm and 85mm look like from shooting photographs on film 15 years ago. Comparing it to s35 would be really confusing.

 

[zaronz]

Just one thing which is VERY important to remember regardless of the cropping are the characteristics of the lens. For instance, the 50mm lens will always have the same characteristics such as depth of field and rendering of the subject regardless of what the crop size is. It will not have the same characteristics like the regular 85mm would just because it is cropped, just like the 35mm(m4/3) lens will have a different look/feel to a 50mm(s35 film) even though the cropping of the m4/3 sensor would make the 35mm almost the exact same FOV as the s35 using a 50mm.

 

[Barry_Green]

Which is why I tried to coin the term "Cinema Crop Factor" or CCF, so we knew what we were talking about (crop factors in terms of cinema cameras).

You say that "35mm stills is the standard" -- well, yes, in the stills world. But ask any ASC member to think in terms of lenses, and do you think they'll convert to stills, and then back to cinema? Of course not. They know what a 35 looks like on a 35mm cine camera, and that's what they'll ask for.

So it does matter, very much, where you're coming from. Do you think people who've grown up shooting APS-C also do some conversion to an irrelevant standard ("full frame 35mm") whenever they talk about lenses? Some may, I don't expect that all do.

Point is -- if you're used to thinking in terms of a 5D, you'll have trouble with cinema focal lengths. So why cling to the old? If you're a scientist, it's better to think and work in the metric system, regardless of where your home country is or what you grew up working with. You may know what a "foot" looks like and how big a "cubic inch" is, but do you bother converting everything between feet and meters and cubic inches and cubic centimeters? Of course not -- you just learn to understand how big a cc is and you forget all about feet and inches.

And thus it should be with cinema. The "5D" "full frame" reference system is the "feet & inches" of the sensor size world. It is as irrelevant to cine shooters as feet & pounds are to the scientist. Metric is a better system for science, and 35mm/S35 is a better baseline for film/video shooters. Constantly referring back to an irrelevant standard is convenient for those who grew up in stills photography and want to cling to it, but -- why not just let go of the old and outdated, embrace the new and go with it?

 

[Barry_Green]

. It will not have the same characteristics like the regular 85mm would just because it is cropped, just like the 35mm(m4/3) lens will have a different look/feel to a 50mm(s35 film) even though the cropping of the m4/3 sensor would make the 35mm almost the exact same FOV as the s35 using a 50mm.

This is not correct. A 35mm lens on m4/3 will deliver an image that looks and feels exactly the same as a 50mm lens on an S35 camera. The perspective will be identical. It is an oft-repeated myth that the wider lenses have perspective differences... they don't. What changes the perspective is how close you move the camera, not what the focal length of the lens is. Put a 35mm on an m43 camera, and a 50mm on an S35 camera, and shoot the identical frame from the identical same position, and you'll see that the images are, in fact, identical in feel, depth, perspective, everything (as long as you equalize out the f-stop to account for the DOF difference).

 

[dishan]

Yeah, I never shot movies on film before, but I've shot photographs. I'll bet most of us have also.
And... quite a few folks shot on DSLRs starting with the 5D. So, whether or not it is "an exception versus the rule", it sort of started this entire fad, and led folks like Vincent Laforet and Phillip Bloom to compare crop sizes to it in the future.

Also, any spec sheet I've ever seen on these cameras compares the crop size to full frame. Even documents and technical specifications from the manufacturer (Canon, Panasonic, etc).

 

[M. Gilden]

Which is why I tried to coin the term "Cinema Crop Factor" or CCF, so we knew what we were talking about (crop factors in terms of cinema cameras).

I like that. I must have missed you trying to coin that phrase, but I agree we should use it.

You say that "35mm stills is the standard" -- well, yes, in the stills world. But ask any ASC member to think in terms of lenses, and do you think they'll convert to stills, and then back to cinema? Of course not. They know what a 35 looks like on a 35mm cine camera, and that's what they'll ask for.

So it does matter, very much, where you're coming from. Do you think people who've grown up shooting APS-C also do some conversion to an irrelevant standard ("full frame 35mm") whenever they talk about lenses? Some may, I don't expect that all do.

I hear you and understand completely. The problem is, with so many folks shooting with lenses designed for full frame cameras, and some folks even referring to lenses that they already own from their photography kits, it feels like we are trying to create a confusing new set of numbers.

Point is -- if you're used to thinking in terms of a 5D, you'll have trouble with cinema focal lengths. So why cling to the old? If you're a scientist, it's better to think and work in the metric system, regardless of where your home country is or what you grew up working with. You may know what a "foot" looks like and how big a "cubic inch" is, but do you bother converting everything between feet and meters and cubic inches and cubic centimeters? Of course not -- you just learn to understand how big a cc is and you forget all about feet and inches.

And thus it should be with cinema. The "5D" "full frame" reference system is the "feet & inches" of the sensor size world. It is as irrelevant to cine shooters as feet & pounds are to the scientist. Metric is a better system for science, and 35mm/S35 is a better baseline for film/video shooters. Constantly referring back to an irrelevant standard is convenient for those who grew up in stills photography and want to cling to it, but -- why not just let go of the old and outdated, embrace the new and go with it?

Thing is, every other forum, site, spec sheet, etc, that is discussing these cameras is doing so in relation to 35mm FF. We would be the odd man out, as a film making forum. If we want to accept some sort of universal standard, shouldn't it be what everyone else is using?

Also, why consider APS-C the "new", and full frame the "old"? I wouldn't mind more full frame cameras on the market...

 

[Kholi]

I like that. I must have missed you trying to coin that phrase, but I agree we should use it.

We've had this discussion back in like 08~9 I think. Whenever the craze started. Half of us concluded that we would stick to what we know (Cinema) and the other half stuck to Photographic measurements (photographers or videographers just coming in.) Funny to see that it hasn't changed at all in a few years.

Part of being experienced is also knowing exactly what lens you need and how many feet to move the camera away. I'm able to do it finally after so long, and typically know exactly what I'm looking for when combining those factors.

I hear you and understand completely. The problem is, with so many folks shooting with lenses designed for full frame cameras, and some folks even referring to lenses that they already own from their photography kits, it feels like we are trying to create a confusing new set of numbers.

They're the old numbers, though. Just in Cinema World. When Full Frame becomes a mainstay in major motion pictures then I think we'll change our way of thinking, but even going up to iMax you think forward, not backward from iMax. I dunno if that make sense in text form...

Thing is, every other forum, site, spec sheet, etc, that is discussing these cameras is doing so in relation to 35mm FF. We would be the odd man out, as a film making forum. If we want to accept some sort of universal standard, shouldn't it be what everyone else is using?

But we are a filmmaking forum, and emulating traditional is what this is typically all about. When I shoot 5D I'm thinking forward into that frame, I know that instead of using a 28-35 as my primary lens for a traditional job, I'm going to result to using 50-60 instead as the main lens. At least for my specific shooting style.

Also, why consider APS-C the "new", and full frame the "old"? I wouldn't mind more full frame cameras on the market...

If it happens, I welcome it. I am a converted fan of Full Frame and would embrace it.

I think I get more confused by people worrying about DOF over AOV and FOV.

 

[zaronz]

This is not correct. A 35mm lens on m4/3 will deliver an image that looks and feels exactly the same as a 50mm lens on an S35 camera. The perspective will be identical. It is an oft-repeated myth that the wider lenses have perspective differences... they don't. What changes the perspective is how close you move the camera, not what the focal length of the lens is. Put a 35mm on an m43 camera, and a 50mm on an S35 camera, and shoot the identical frame from the identical same position, and you'll see that the images are, in fact, identical in feel, depth, perspective, everything (as long as you equalize out the f-stop to account for the DOF difference).

I appreciate the justification and am thankful about the correction of the perspective myth. Obviously.. I appear to be a victim of the myth about lenses and their perspective differences. However, as you mention to equalize the f-stop the account for the depth of field differences. Are you by that implying that the 35mm(m4/3) and the 50mm(s35), both at F2.0 would accomplish a different depth of field?

 

[dishan]

I appreciate the justification and am thankful about the correction of the perspective myth. Obviously.. I appear to be a victim of the myth about lenses and their perspective differences. However, as you mention to equalize the f-stop the account for the depth of field differences. Are you by that implying that the 35mm(m4/3) and the 50mm(s35), both at F2.0 would accomplish a different depth of field?

yes- the further the zoom, the shallower the DOF. That is why a 5D is capable of more bokeh in the same scene than an APS-C camera is. Using a 50mm on a larger sensor will be more telephoto and result in a shallower DOF within the same FOV than using a wider lens on a smaller sensor to achieve the same field of view.

 

[zaronz]

yes- the further the zoom, the shallower the DOF. That is why a 5D is capable of more bokeh in the same scene than an APS-C camera is. Using a 50mm on a larger sensor will be more telephoto and result in a shallower DOF within the same FOV than using a wider lens on a smaller sensor to achieve the same field of view.

That was my assumption about how full-frame accomplishes the depth it does and I am glad I wasn't misinformed on that as well.rogar-Happy(DBG): However, that was the most important point in my original post as well(although I may not have emphasized that point enough). But, hey.. kudos to you for the clarification!

 

[Kholi]

yes- the further the zoom, the shallower the DOF. That is why a 5D is capable of more bokeh in the same scene than an APS-C camera is. Using a 50mm on a larger sensor will be more telephoto and result in a shallower DOF within the same FOV than using a wider lens on a smaller sensor to achieve the same field of view.

Less telephoto.

 

[dishan]

Tomatoes, tamatoes...

But yeah, my mistake.