Should Full Frame lenses be avoided?

Psynema

Psynema

Well-known member
Just a thought I had.

Ordered the 85mm Rokinon, BUT in a Canon, not Olympus 4/3, mount. Used an adapter.

Purple and Green fringing out the wazoo. I know this is normal for cheap/wide open lenses, but haven't heard this complaint about the 85mm, so I'm asking...

Is it possible, even with the adapter, that fringing gets exaggerated because the Canon lens is on a sensor have the size? I'm now wondering if I get the Oly version if it would be as bad.

Not that the lens is terrible, but the PF is noticeable without pixel peeping. I know using the crop mode exaggerates PF and noise as well, just wondering if using a full frame lens on a 4/3 sensor has the same effect.
 
Yes, the 2x crop factor of micro 4/3 relative to full frame is going to make full frame lenses look worse. Color fringe will be blown up by 2x. Everything will look 2x softer (less resolution) than on a full frame camera. Some of this is offset by the fact that you are only using the center portion of the lens, which is usually sharper and has less chromatic aberration. But, it is usually not 2x sharper than the corners of the full frame, so will still take a hit in resolution. Some people actually like this softness.

Having been an old Pentax film camera user, I tried a bunch of my old Pentax lenses on my GH13 using an adapter. What I found was that I get a lot more color fringe and lower resolution than the native micro 4/3 lenses. So, I concluded that the only full frame lenses worth using on micro4/3 if you want sharpness as good as the native lenses, are the highest quality full frame lenses. I bought a Canon FD 500mm f4.5 L lens because I do a lot of bird photography and video. It is an extremely high quality lens and it is as sharp as micro4/3 lenses and has almost no color fringe due to the flourite glass. I find it acceptable to mix this lens with the micro4/3 lenses. Otherwise, I have chosen to stay with micro4/3 native lenses in order to get best results. It costs more because the lenses are new, but the native lenses are by far the sharpest because they are made for the format.
 
Interesting never realised this with PF before, so I guess the same would apply to using any lens designed for a FF 35mm camera on an APS-C sized sensor too, though of course not as bad as on a m4/3
 
So I should trade/exchange this Canon mount Rokinon 85mm in for the Olympus version then?
 
joe - so you're saying the mechanics are the same - ie an Oly lens would theoretically cover a full frame since they double dipped vs. angling the light for a 4/3 sensor?
 
My Pentax mount Rokinon 85mm F1.4 works on both the Pentax DSLRs with APS-C sensor and 35mm Pentax SLRs. I also use it on my GH2 and I bet the optics are the same on the Canon, Nikon and Olympus mount versions.

Here is a shot I took with my Pentax *ist DS2 DSLR before I purchased the K-7 in early 2009 with it wide open:
ACDWallpaper.jpg
 
I think that the ideas mentioned in the first few comments are a bit moot, as the resolving power of almost all of these lenses is several times greater than the 2K footage we are recording with them.

For stills, perhaps there is some small truth in the claims that the eg 16MPs of the GH2 on 4/3 (which would result in about a 35MP image were it full frame), might perhaps tip some lenses beyond their resolving power, but the resolving power of a lens is only one aspect of performance, and there is nothing to suggest that the Lumix 4/3 lenses can resolve better than a Contax G 45 F2, for example.

I have never seen purple and green fringing on my GH1 with my manual lenses - I'd puke if I did - it's one characteristic I can't tolerate in the slightest.
 
Lucas Adamson said:
I have never seen purple and green fringing on my GH1 with my manual lenses - I'd puke if I did - it's one characteristic I can't tolerate in the slightest.
Click to expand...
It's a property of the lens, not of the camera. Most lenses will exhibit it when at fully wide-open, even my set of Compact Primes and Zeiss ZF lenses all show it. Open up any of your lenses all the way and point at a black & white chart or some words on a page or something, and you'll see it.
 
I've had a lens or two, such as a 20mm f3.5 Cosina cheapie that had horrible massive corner fringing on my old 5D, but I'd hazard a guess that if I'd kept it, it would be fairly clean on the GH cameras due to the crop. Surely most fringing is in the corners, and we don't see them at all on m4/3.
 
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