So does this lens has the FOV of a 14mm lens at the wide end when it is corrected or uncorrected?
(Since it has significant barrel distortion at the wide end)
(Since it has significant barrel distortion at the wide end)
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For me (as stated earlier), the 'big deal' is that geometric distortion correction can accentuate the effect of volume anamorphosis. Ok, so it'seo not really a big deal for me personally, because i don't use DPP so the geometric correction won't be forced, and DPP can't correct volume anamorphosis anyway. Given that, the trade-off of a 14mm wide end and 77mm filters is a good one (or would be, were I planning to buy the lens – I'm not, since I'm good with the adapted EF 16-35/4 and EF 11-24/4).There are very few lenses that don't need any distortion correction right? Even good EF lenses need a bit of pin-cushion or barrel distortion correction. So since people are going to have those corrections turned on anyways, what is the big deal if the trade off for more distortion in an uncorrected lenses is the fact that I can use the same filters on the 14-35, as I do on my 24-105 f4, and 100-500??
14mm FoV after correction. That's clear from Bryan's statement that the the QA-77 chart (based on ISO 12233) he uses was captured at 14mm using the framing marks on the chart (i.e. framed using the EVF or LCD where the geometric corrections are applied live), but the RAW image viewed in C1 showed a wider framing with heavy distortion.So does this lens has the FOV of a 14mm lens at the wide end when it is corrected or uncorrected?
(Since it has significant barrel distortion at the wide end)
Thanks!14mm FoV after correction. That's clear from Bryan's statement that the the QA-77 chart (based on ISO 12233) he uses was captured at 14mm using the framing marks on the chart (i.e. framed using the EVF or LCD where the geometric corrections are applied live), but the RAW image viewed in C1 showed a wider framing with heavy distortion.
Maybe I'm missing something, but isn't there another aspect to this 'correction' beyond the geometric distortion? The output image file size is fixed for a camera, e.g the R5 outputs a 45 MP image, 8192 x 5464 pixels. When I take the 14mm RAW file viewed in C1 and manually correct the barrel distortion then crop to the area that is a 14mm FoV (the 3:2 framing marks on the chart), the resulting image is ~12.5% smaller, e.g. an R5 image post-correction would only be ~39.4 MP. To output a 45 MP file, that would need to be upscaled.As for other ppls comments about the loss of mm after correction, we already know from other corrected canon lenses that after correction it is 14mm while the images without correction is in fact wider to allow for the correction.
So if the image after correction has a 14 mm FOV and it sharp, then who cares about any distortion of the "raw" image? It doesn't really matter in the end.
The barrel distortion is the compromise you end up with given a flat 77 mm front element. The alternative would be a big heavy bulging front element ala Tamron 15-30.
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In all this looks like a nice lens. I would have preferred a few extra mm at the long end (e.g. 16-40) but that's not what's on offer.
If - for some weird reason - you want a 45MP JPEG, then yes.Maybe I'm missing something, but isn't there another aspect to this 'correction' beyond the geometric distortion? The output image file size is fixed for a camera, e.g the R5 outputs a 45 MP image, 8192 x 5464 pixels. When I take the 14mm RAW file viewed in C1 and manually correct the barrel distortion then crop to the area that is a 14mm FoV (the 3:2 framing marks on the chart), the resulting image is ~12.5% smaller, e.g. an R5 image post-correction would only be ~39.4 MP. To output a 45 MP file, that would need to be upscaled.
If true, then not only is there a loss of IQ in the corners where the image is stretched to correct the distortion, there's also an overall loss of IQ when the resulting image is upsampled to the camera's normal output size.
There would be no if about it. The R5 and DPP are going to output images that are 8192 x 5464 (for the R5, obviously other camera have different output sizes), even though they need to be upscaled to get to that fixed output size. What algorithm is Canon using for upscaling? How good is it? We won't know, it's a black box, but regardless upscaling is adding information to the file that was not in the original scene.If - for some weird reason - you want a 45MP JPEG, then yes.
The distortion is shocking. While I hate the idea of an adapter, no IQ improvement is worth the field curvature with this lens. All of that extra sharpness will get lost in post.
Note that I'm not positive that's the case – maybe this lens on an R5 will yield a 39.5 MP image at 14mm, a 41 MP image at 16mm, etc. I doubt it, but I really don't know. Since Canon does a similar 'trick' with the RF 24-240, it would be occurring there as well and I haven't heard anyone mention that the 24mm images from the superzoom are lower resolution.
I've read the review and I have a lot of thoughts about this lens...and a lot of skin in the game, as I have TWO of them pre-ordered.
This is a very small lens. So small, in fact, that I am willing to forgive some of these perceived flaws because it will bring down the size/weight of Canon's ultra-wide lens options tremendously. If you don't value size and weight, then why are you even considering an f/4 lens? Go buy the f/2.8 and stop acting like anything slower than f/2.8 has no place in your bag at any price. LOL
I'm desperate for this lens. I am DONE adapting my EF ultra-wide and I'm eager to get to work with this thing. Is it perfect? No...and the RF 15-35 has some major flaws of its own - just like every other manufacturer's ultra-wide lenses. This, however, is the smallest and lightest I have ever seen, takes a 77mm filter and will be joining my camera bag by the end fo the month.