Lunar Eclipse PICS with the EOS Ra, EOS R6 & EOS M6

Marco Nero wrote:

Thomas A Anderson wrote:

Marco Nero wrote:

Larawanista wrote:

Dude, your 8th photo is CHAMP!!! Everything else is of course very good!

And I thought the EF24mm 1.4L isn't for astro?

I shot at f/2 (to eliminate some of the coma) with an 8 second exposure using ISO 2500. The EF 24mm f/1.4L II was recommended to me by Canon for photographing the night sky, especially with Auroras. I have not yet had the chance to test that out yet. But I suspect this lens will eventually be superseded with an obscenely expensive RF version before long.
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The really strange thing about this lens is that it Vignettes quite stongly on the EOS Ra but not the EOS R6. The EOS Ra is simply an EOS R with two modifications. The vignetting on that camera makes no sense to me, and it's quite disappointing. It can't be corrected and simply must be cropped. Or another lens used instead. Canon have not been able to explain why this happens and seem to think it might be "caused by the use of a lens adapter". Yet the R6 uses the same adapter and lens with no vignette. It's a bit puzzling to me.
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EOS Ra with the same lens (unedited) showing hard vignetting, even without a filter or a lens hood on the lens. Quite a mystery.

Looks like Distortion Correction is turned off. If it was vignetting there would still be something in the corners, but rather than just dim it's absolutely black. If one camera had distortion correction on and the other off this is what you'd get. As noted in the R manual on page 111 the image is cropped when Distortion Correction is enabled.

I just checked. Here's my settings for the EOS Ra with the EF 24mmL lens (which is recognized by the camera):
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Peripheral Illumination Correction = ON
Distortion Correction = OFF
Digital Lens Optimizer = ON
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This isn't Light Falloff (soft vignetting), this is Hard Vignetting. And Canon's wasn't able to explain why it's happening with just this camera. I note that some models of the EOS 5D (3?) would also vignette harder with this lens than the EOS 6D did. Since the EOS Ra is simply an EOS R with two differences (30x magnification + Modified Sensor), the menu is the same. We ran some threads of this a while ago (last year) and nobody was able to determine the cause of the Hard Vignette with this camera+ lens combo.
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I'll be sure to test the camera with the Distortion Correction ON. Whilst this will crop the image slighty (however much "slightly" is), hopefully it will render this lens more useful on the Ra - in the sense that I can crop in-camera. Though cropping at home makes a lot more sense since I'll have more control.

My assumption (as stated in another response) is that it's not just cropping but also doing some correction around the edges. I kind of wonder if some cameras keep Distortion Correction switched on by default, but maybe you switched yours off upon initial setup? I typically turn off corrections when I'm setting up the camera.....although now that I'm thinking about it if DC was set to on I'm not sure I would have turned it off. Now I'm going to have to go check on that. Anyway, the first thing I thought when I looked at the image was stacked filters or a generic hood that was too long, but since that's not the case the next thing I thought was "that looks like an uncorrected image from a point and shoot with a wide angle zoom."

Vignetting to me implies there's still some light in the corners of an image.  It may be strong or weak, but light falloff in the corners implies there is still some of the image circle in the corners, just dimmer than the center of the image. If there's no light any more it's just outside the image circle, not a dim perimeter of an image circle that only appears to be "in the corners" because rectangular sensors crop a round image projection.

I think this is why it would be hard to diagnose such a problem.  Most people when they see an EF lens would never assume that the image circle doesn't cover the entire imaging frame.  However, EF lenses designed in the last ten or so years certainly catered to digital bodies in so many obvious ways (AF accuracy and controlling where the plane of focus is in the DoF, AF speed, and even RF lenses have a lot of improvements over EF counterparts while having darker corners that relies on in-camera correction).  So I find it plausible that more modern EF lenses actively rely on correction for digital shooting.