T-mount Leica lenses on FF?

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PJ711 Regular Member • Posts: 459
T-mount Leica lenses on FF?

Pardon if the question has been addressed, but has anyone had experience with cropped lenses on the FF bodies? I got the Sigma FP with the 45/2.8 kit, and know that it has a crop mode for these lenses. But has anyone tried them without a crop? I've had success with a Pentax film camera using certain APS Pentax lenses, but not others.

Any real-world experience from you guys would be appreciated.

MOD Tom Caldwell Forum Pro • Posts: 41,270
aps-c image circle lenses on FF?

PJ711 wrote:

Pardon if the question has been addressed, but has anyone had experience with cropped lenses on the FF bodies? I got the Sigma FP with the 45/2.8 kit, and know that it has a crop mode for these lenses. But has anyone tried them without a crop? I've had success with a Pentax film camera using certain APS Pentax lenses, but not others.

Any real-world experience from you guys would be appreciated.

Not much help from me - maybe others might be able to help.  With lenses that communicate with the camera body it seems that the camera will go into auto-crop mode and there there is no vignette.  However as far as I know there is no way to optionally switch this off.

Recently I bought a cheap Neewer 85/1.8 MF lens in dumb EF mount which was sold as “aps-c” image circle which I have successfully used on M4/3 camera bodies.  Tried it on my S1 to see “how bad” the vignette might be I found “no vignette” at all.  Either the lens has a FF image circle (most likely) or somehow it manages to do auto-crop with a lens that is completely dumb and has no communication with the camera body at all (which would be extraordinary).  I have not bothered to get the images off my camera to check file sizes - I will do this in time out of curiosity.

In any case that lens is a very cheap and cheerful lens that produces images above what its price bracket might suggest that seems to work well on L-mount bodies with a suitable adapter.

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Tom Caldwell

eFilm Senior Member • Posts: 1,887
Re: T-mount Leica lenses on FF?

PJ711 wrote:

Pardon if the question has been addressed, but has anyone had experience with cropped lenses on the FF bodies? I got the Sigma FP with the 45/2.8 kit, and know that it has a crop mode for these lenses. But has anyone tried them without a crop?

Electronic APS-C L-mount lenses such as the Leica T lenses work in crop mode only. You can only switch between crop mode and FF mode with electronic FF lenses or with fully manual lenses.

I think that's fine. I don't mind the 'forced' crop for electronic crop lenses.

OP PJ711 Regular Member • Posts: 459
Re: T-mount Leica lenses on FF?

eFilm wrote:

PJ711 wrote:

Pardon if the question has been addressed, but has anyone had experience with cropped lenses on the FF bodies? I got the Sigma FP with the 45/2.8 kit, and know that it has a crop mode for these lenses. But has anyone tried them without a crop?

Electronic APS-C L-mount lenses such as the Leica T lenses work in crop mode only. You can only switch between crop mode and FF mode with electronic FF lenses or with fully manual lenses.

I think that's fine. I don't mind the 'forced' crop for electronic crop lenses.

What confuses me is that the FP menu has a crop mode setting submenu which includes "off" (there is auto, on and off to be exact).

Which leads me to think that the body is in charge, not the lens. Which suggests that the Leica T 23mm pancake could be a wide-angle 23mm with a vignette (or not) or a crop 35mm depending on how the body is set. Which wouldnt be a bad thing.

LOL I'd prefer if I could find out if anyone has actually done that though.

eFilm Senior Member • Posts: 1,887
Re: T-mount Leica lenses on FF?

PJ711 wrote:

What confuses me is that the FP menu has a crop mode setting submenu which includes "off" (there is auto, on and off to be exact).

The crop menu is not there for native crop lenses. It's there for the user to be able to switch between full frame and S35 video mode with full frame lenses, and it does work with photos, too.
It also enables you to use manual or non-native electronic lenses made for S35/APS-C cameras. Most non-native lenses won't crop automatically.

I won't go into detail why the camera does what it does, but suffice to say it does work and it does make sense to those who actually need the feature.

Native APS-C lenses work just like they're supposed to with the fp. Which is a good thing.

Which leads me to think that the body is in charge, not the lens.

It's possible that native lenses may have been 'hard wired' to display only APS-C mode, which makes sense, but that's beside the point. The body usually is calling the shots.

Which suggests that the Leica T 23mm pancake could be a wide-angle 23mm with a vignette (or not) or a crop 35mm depending on how the body is set. Which wouldnt be a bad thing.

Actually it's always a 23mm wideangle lens which covers an APS-C -sized image circle. Within the APS-C sized frame the angle of view is about the same as the angle of view of a 35mm lens that covers a 24x36mm frame. It's never a 35mm lens.

LOL I'd prefer if I could find out if anyone has actually done that though.

I simply reported what the camera does with the crop TL lenses.

If you want to play with it yourself you can try covering the electronic contacts with some thin, non-conductive tape and thus make the lens a 'manual' lens.

I don't recommend, nor do I see the point of that, though. After all, it would be a fixed aperture, fixed focus lens that would deliver an ugly, vignetted and distorted image with possible other unsightly aberrations as well.

Keep in mind that the modern electronic lenses are being corrected digitally, and disabling the electronic contacts will disable that. Nor has the lens been designed to cover a full frame, anyway. So why ruin the image of an otherwise nice and fairly pricey lens that way. I'd rather just pick some nice & compact 24mm or 35mm M-mount lens instead.

But whatever floats your boat.

OP PJ711 Regular Member • Posts: 459
Re: T-mount Leica lenses on FF?

Forgetting the old adage, when in doubt read the manual,

The fairly detailed FP user guide gives me the answer:

crop mode will result in a 9.8mp image which will be a 7.1MB file in fine setting, 14 bit DNG.

I can turn it off if I like, so the sensor will capture the entire image. Still don't know if/how much vignetting will occur. Based on my experience in the Pentax system, some lenses are practically or entirely vignette-free, others have strong vignetting, particularly the shorter ones.

So I suspect the Leica 23mm would vignette if used as a true 23. But I'd want to use it as designed, to give me a 35mm angle of view.

Thanks for your observations guys.

D Cox Forum Pro • Posts: 26,759
Re: T-mount Leica lenses on FF?
1

If you set it to always use the whole sensor, you can always crop off any vignetting, or crop the worst part and correct the not-so-bad part in processing.

Cropping to a square will give you more pixels than a straight crop to APSC.

 D Cox's gear list:D Cox's gear list
Sigma fp
OP PJ711 Regular Member • Posts: 459
Re: T-mount Leica lenses on FF?

True, I suspect you could get very useable 3:2 crops to approx. 28mm equivalent.

I imagine the advantage of in-camera cropping is how the image appears on the screen. There are options on the FP for black lines vs. transparent lines.

Basically I'm a street shooter and want the option to go to 28-35mm FOV when appropriate. I do really like the 45/2.8, and have been shooting with it on the FP (its my only lens for the camera). The results so far have been great, at least for my needs.

Maybe the Leica 18/2.8 pancake is what I'm looking for.. the occasional wide to pair with the 45, even if the resulting file is smaller, I'd get to keep the full frame pixel size IQ. I've printed 12x18 inch from 10MP files from my long-gone Leica M8, and have no doubt that I could do the same from the FP.

Sorry for my musing ramble, it really is an interesting camera for these adaptations.

eFilm Senior Member • Posts: 1,887
Re: T-mount Leica lenses on FF?

PJ711 wrote:

Basically I'm a street shooter and want the option to go to 28-35mm FOV when appropriate. I do really like the 45/2.8, and have been shooting with it on the FP (its my only lens for the camera). The results so far have been great, at least for my needs.

Maybe the Leica 18/2.8 pancake is what I'm looking for.. the occasional wide to pair with the 45, even if the resulting file is smaller, I'd get to keep the full frame pixel size IQ. I've printed 12x18 inch from 10MP files from my long-gone Leica M8, and have no doubt that I could do the same from the FP.

I've got that lens and yes, when attached to the fp it's an attractively sized package, especially when you add nothing or just the smallest Sigma hand grip to the camera. As a bonus for street shooting it's completely silent. In fact, the focus motor or the aperture mechanism will be making the only noise when active.

You'd get a nice little lens that will give you the same kind of image you get with a Leica TL/CL with it, only with slightly less megapixels, as it's cropped from a 24mp full frame sensor. It's not too bad, and like said, the size is attractive.

However, it is still a 18mm lens and I kinda prefer the look I get from an actual 28mm lens in full frame mode. It's not about the missing megapixels, but about the subtle difference in the look the ten extra mm provide. Anyway, it would still be quite a usable little lens for street shooting, and the results aren't too shabby.

ronald weissman Regular Member • Posts: 288
Re: T-mount Leica lenses on FF?

While T-mount lenses don't cover the sensor and yield 9MP images on the FP and S1, (and 20MP images on the SR1), they are superb for video. Small, light, extremely sharp. They pair well with the FP, SL2 and SR1 and provide full sensor coverage for 4K. They focus about as well and fast as most other native lenses on the FP and SR1.  They, of course, retain their APS-C focal length when used for video.

 ronald weissman's gear list:ronald weissman's gear list
Leica CL Fujifilm GFX 50R Panasonic Lumix DC-S1R Fujifilm GFX 100 Sigma fp +8 more
ronald weissman Regular Member • Posts: 288
Leica TL 18-56mm is a perfect FP 4K video lens

Further on this topic the TL mount  Leica 18-56 is a perfect video lens for the FP, perhaps the best I've used so far.  It is small and light, optically excellent, has a very easy and smooth zoom, and it the best, so far, at autofocus on the FP.  While no lens is very good with FP autofocus in my experience, this is among the best. It finds focus relatively quickly, even faster when aided with a tap of the shutter button.  This lens is a fraction of the size and weight of any of the L-Mount full frame zooms.  Highly recommended.

 ronald weissman's gear list:ronald weissman's gear list
Leica CL Fujifilm GFX 50R Panasonic Lumix DC-S1R Fujifilm GFX 100 Sigma fp +8 more
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