GH4 Lenses made for GH4?

CustomerGH4 said:
2.3 is with full frame. With native lenses the crop is 2.6 instead of 2.3
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Not sure what you mean by this ?

Why would native lenses have a different crop factor ? The whole crop factor thing has always been relative to the Full Frame 35mm still photo format.

As far as I know any matching focal length lens will always have the SAME FF crop factor, so whether the lens is an old Nikon AI-S or a native Panasonic lens the crop factor is the same.
 
I thought that the adapted lenses because of an adapter or speedbooster change the crop factor to 2.2 and 2.3.
But when using natives its 2.5 and 2.6
Im not really good with numbers.

Im reading this atm and in the down below calculations it is 2.5 and 2.6 as well. http://gh4crew.co.uk/?p=460
 
um... huh? No. The crop is 2.3 and 2.3 is the crop. With lenses, a 50 is a 50 is a 50 - only the coverage circle changes.

edit: just noted the follow-up link with all the math etc... Hm. Well, maybe it's 2.5, but it doesn't feel like it. Same method applies: use a wide lens and step forward or back. I'm curious of some of his claims and methods in that article, as he mentions the "multi aspect" sensor being a constant 2x crop factor, when thorough examination back in the GH2's day read its crop in 16:9 video mode as 1.8something_x... and the AF100 is stated as 2x in all sorts of literature, and the GH2 in video mode is clearly wider than the AF100.

...quick search mentioned the A7S having a 1.1x crop factor in 16:9; makes me curious if/what the exact 16:9 crop factors of various cameras are, and also makes me wonder if it all really matters as long as it's in the same ballpark.
 
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This is what I've been using to calculate the GH4 format crops: FF sensor width / GH4 sensor width * GH4 sensor pixel width/4K format pixel width

So for DCI it looks like this: 36/17.3 * 4608/4096 = 2.34x 4K DCI FF crop factor

And for UHD it looks like this: 36/17.3 * 4608/3840 = 2.50x 4K UHD FF crop factor

...I sometimes forget that the m4/3 crop is only 2.0x when using the full 4:3 format sensor size. ( the GH2 had a multi-aspect sensor which compensated for different shooting formats )
 
It would be awesome if the mft lenses would have all the focal lengths (in 35mm terms) for the GH4 marked in the manual for each mode or even better, on the box.
That way it would be easier then to calculate everytime when getting a new lens.
 
We really do get hung up on the whole crop factor thing. Just use a lens that fits the fov you want on the GH4. It doesn't really pay to always think in terms of FF when you are shooting with a GH4. Just think of the GH4 and shoot with it. Take a small step back which is really all the difference there is.
 
Bruce Foreman said:
Why get "hung up" on the "numbers game". Both still photography and motion picture are VISUAL mediums, not "math games". To me it's real simple, past the increased definition I don't care about HD, UHD, or full 4K, or whatever. If I need wide I grab a wide lens and SEE visually how I can make it fit what I need. In the years I spent in the film ages doing some documentary work, some photojournalism, I learned to depend on the full frame 28mm as a "workhorse" wide angle lens.

Give or take a silly millimeter (or two), I'm not going to care. I can just put the lens on the camera and get what I need.
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seriously who cares. Look at your subject and if you need a different lens switch it, if you want to be a little tighter move forward. I started with the gh2/gh3 then tried using a canon 6d and HATED how short of a range the lenses were. I like the feel of the 2x crop MUCH better and feel like they cover everything a lot better.
 
Boom!
Just as I suspected, the fisheye for example loses its effect with the crop in 4K. So its not just "deal with it and use the lens you need" because when one wants a proper fisheye effect in 4K he/she gonna have some trouble with it.

 
No, exactly. A lens will have the same bokeh (which is a multi-faceted character of specific lenses, not a quantifiable number) regardless of which body it's used with... the image is just cropped on a crop sensor and the field of view will be different. The depth of focus at a certain aperture IS a quantifiable number, and is also independent of the body on which the lens is used - again, the image is just cropped on a crop sensor and the field of view will be different.
 
CustomerGH4 said:
Boom!
Just as I suspected, the fisheye for example loses its effect with the crop in 4K. So its not just "deal with it and use the lens you need" because when one wants a proper fisheye effect in 4K he/she gonna have some trouble with it.
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You can get wider fisheye optics. You can get them so wide they make a circular image within the frame, crop to what you need. You'll have to go with adapted "legacy" lenses to do this but there is a way.

A word about "fisheye" perspective. It's a "gimmick" that wears thin very quickly if used much. In my own studio business NONE of my clients wanted anywhere near that kind of look on anything. Plain and simple, they wanted no part of "gimmicky" distortion, on all wide perspective images they wanted rectilinear (no, that's not a medical term) correct lines. In my 13 years working for an air force photo dept they supplied us with no such extreme optics, if any of us owned one (I didn't) and used it on assignment, rarely did such an image get used. One exception was aerial work in very confined spaces, this was mostly in the film era, we were shooting slide film and there was no convenient way to "de-fish".

Professionals have always had to learn the limitations of gear, know how far to "push it", and work within those limitations to get the images needed.

In the video above, for the 4K crop to deliver close to the same perspective as the 1080p one would (in most cases) simply need to move back some. If you need wider than he could get with the 12-35mm lens, I have an Olympus 9-18mm f4-f5.6 Ulra Wide Angle that is rectilinear correct (no curved lines) giving me 18-36mm FF equiv.

I don't know if you simply never got the grounding in basic photography to be flexible enough to reach for the options you have, or if you are one of those who have to get everything handed to you absolutely perfect.

Bern Caughey "nailed" with his statement on it being up to the photographer to learn his tools.

You might consider that you may be a source of entertainment and amusement to those of us who have.
 
Bern Caughey said:
Your right, & everyone else, including Denny Clairmont, is wrong?

http://www.oscars.org/press/pressreleases/2011/20110107a.html

If you have an iOS device get a copy of pCAM.

http://www.davideubank.com/Good_Focus/pCAM_FILM_+_DIGITAL_PRO.html
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Give D.Clairmont GH4, a 50mm lens and let him record in HD, UHD and 4K and ask him if 50 is still a 50.
The examples he brought were between FF35, S35 and 16mm sensor, but not MFT and especially GH4.
Its safe for me to say that crop factors do exist and 50mm is not 50mm. If it was then why its called 25mm on MFT and why the exif data shows 54mm? Or alas if put a 50mm full frame lens on mft via adapter why the focal lenght is still not 50mm?
image.png


The app seems handy though.
 
Bruce Foreman said:
A word about "fisheye" perspective. It's a "gimmick" that wears thin very quickly if used much. In my own studio business NONE of my clients wanted anywhere near that kind of look on anything. Plain and simple, they wanted no part of "gimmicky" distortion, on all wide perspective images they wanted rectilinear (no, that's not a medical term) correct lines. In my 13 years working for an air force photo dept they supplied us with no such extreme optics, if any of us owned one (I didn't) and used it on assignment, rarely did such an image get used. One exception was aerial work in very confined spaces, this was mostly in the film era, we were shooting slide film and there was no convenient way to "de-fish".
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Everything is a gimmick if its used too much, but that does not mean there would not be situation when a "gimmick" might come handy. Lets say for example skateboard videos or an artsy shot. And there are even IMAX Domes that project fisheye lens projection onto the dome. You never know when you might need a fisheye lens. And yes photo/videographers need to learn their tools, that is why Im asking here about the tools, because MFT is a new format for me. Previously my only experience with "DSLR" was Canon 5D Mark II with Carl Zeiss Compact Prime CP2 7 lens set, so yeah, I do not have much knowledge with adapters and Zuiko and Panny glasses and different FOVs available in MFT, but that is why Im here to find out the limitations and how to go over them.
 
The lens doesn't change when the sensor changes. With different sensors, different focal lengths will give you a "normal" field of view... But the focal length of the lens (25, 35, 50) never changes. It might even be on the same body - say an A7s. In its normal full frame mode, a 50mm lens gives an equivalent field of view of a 50mm lens on a full frame camera. Switch that same camera to APS mode with an approx 1.5x crop, and that 50mm lens now yields an equivalent field of view as a 75mm lens on a full frame camera. The lens never changed, the properties of the lens like its bokeh, depth of field, speed, etc didn't change, but the sensor did. It's just like your picture illustrates: the lens is still throwing that full image towards the back of the camera, but the sensor only captures a certain part of it.

when selecting lenses for a crop system and you're used to full frame, just keep that crop factor in your head and you'll be fine.

Get a Rokinon 8mm fisheye if you want a fisheye. It even works on a SpeedBooster. Natively, there's the Panasonic 8mm and Rokinon 7.5mm.
 
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