24/1.4 II @ PZ

Discussion in 'Canon EOS' started by yakim_peled|1, May 17, 2010.

  1. Yes, there's no way around that, and it's a huge problem for those that shoot planar subjects at the widest aperture ;)
    Seriously, if you think of those cases when you'd use a lens wide open – portraits, low-light etc. – corner sharpness is rarely an issue: either the main subject is located in the centre and/or the corners are way off the focal plane and therefore blurred anyway.
     
  2. I wonder why it is more difficult to design a fast aperture prime than a slower (but still fast) zoom. Look at the results of the 70-200/2.8 IS II. And FWIW, I shoot a lot of portraits (always wide open for shallowest DoF) and my subjects are very rarely in the center. I usually find it boring - composition wise - when my subject is dead center.
    Happy shooting,
    Yakim.














    00WTjQ-244749684.jpg
     
  3. Another one. Both with 135/2 on 7D. Yes, I know it's a longer FL but I do the same with shorter ones. Just a personal preference I guess. I wonder if I'm so different than others.
    Happy shooting,
    Yakim.
    00WTjX-244751584.jpg
     
  4. I didn't mean dead-centre. Your 2nd example is well within what I would regard the better-performing centre area of a lens. And notice that the hair and shoulder are beyond the focal plane. While the welder is placed at the periphery, the corners are again not in the focal plane. So corner sharpness isn't an issue.
    Regarding lens design, wide angles seem to be more prone to vignetting than longer FLs. The long and extremely fast tele lenses usually display only moderate vignetting even used wide open.
    Besides a bit of vignetting can also enhance an image, so it isn't necessarily a bad thing. It's easy to control in software, too.
     
  5. Personally, I'd like to have less vignetting and especially, more corner resolution. This is because I'd rather have a base file which needs as little as possible PP and a lens which would put as little limitations to what I want to do. YMMV of course.
    Happy shooting,
    Yakim.
     
  6. To make a lens with less vignetting, you need a larger image circle. You get that with the 24-TSE. I would expect that an f/1.4 lens with a much bigger image circle would result in a dramatically larger and more expensive lens.
     
  7. In fact, I'll go ahead and speculate on how big it would be. It would be great if someone who is a real optics expert could chime in! I'll assume that the f-ratio is simply the focal length divided by the aperture diameter, which I don't believe is quite correct for this kind of lens, but it's probably close enough for a fun approximation.
    If f/2.8 corner illumination performance is good enough, then to get that same result, you'd need a lens that is twice the diameter of the real lens' 87mm: 17cm! If f/5.6 performance is what is necessary (what PZ says represents vignetting which is no longer field relevant), then you're looking at a lens that is 4x the diameter, or 35cm!
    Weight might well increase by the cube--8x and 64x respectively. If they were produced in quantity, cost might track with weight, but of course they wouldn't so even $100,000 couldn't buy you that 42kg lens. But at least PZ would say that wide-open vignetting was at last no longer field-relevant!
     
  8. I shoot a lot of portraits (always wide open for shallowest DoF) and my subjects are very rarely in the center. I usually find it boring - composition wise - when my subject is dead center.​
    Portraits? I'm no expert but I suspect that many landscape shooters will drool when they see the overall resolution at f/5.6 of this particular lens. But, true, if you really want to use it for portraits on full-frame, you will have to either avoid putting crucial elements in the extreme corners or stop down to, say, f/2.8 or f/4. And if you shoot, say, historical documents for billboard reproduction and want to throw the paper plane out of focus while keeping the ink clots sharp, look elsewhere.
     
  9. My line of thinking is that people usually buy fast lenses (2.8 and faster) in order to use this fast aperture most of the time. I may be wrong though. Would not be the first time. :)
    Happy shooting,
    Yakim.
     
  10. Yakim, I think the two examples you provided would work fine with the 24/1.4 working at large apertures--the center of interest doesn't have to be in the exact center of the frame to be sharp enough to pop out of the background bokeh.
     
  11. I would take whatever I read on photozone with a grain of salt. A lot of fast lenses will vignette and soften when shot wide open. If you are concerned about vignetting, stop down and it should be gone. The same goes for the soft edges. This is the sharpest and the fastest 24mm lens you'll be able to get your hands on. It'll outperform the 24-105mm 4.0L, 24-70mm 2.8L, and the 16-35mm 2.8L at 24mm.
     
  12. high amount of vignetting and low corner resolution​
    I wonder if the low corner resolution is actually a resolution problem or field curvature not accounted for in the test procedure.
     
  13. Jeff Ascough, the wedding photographer, makes good use out of this lens on both the 5D Mark II and the new 1D Mark IV. It is a fantastic lens apparently. I have to say that the new Nikon version of the 24mm 1.4 has gotten better reviews than Canon's version for what it's worth. I think this is pretty much a quibble for those who can afford the lens and make good use of it. To me right now some of the L prime line up of lenses are very tempting but I'm not able to prioritize them at this time.
     
  14. Both with 135/2 on 7D.​
    On a full frame camera, the extreme corner point is a little over 20mm from the corner; on a 1.6x crop, it's a little over 10mm. Around 13 or so. On a 1.3x crop, it's a little over 15. 16 something. I remember them as being roughly 1/2 and 3/4. That's not precise, but it's close enough for examining MTF charts.
    Look at Canon's published MTF chart for the 24:
    http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=151&modelid=17623
    Cover from 13.4 and everything to the right. Basically, you'll be using about the left half of the chart. For a wide angle, that's pretty impressive.
    Compare the 24/1.4 II to the 24-70/2.8, and you'll see the prime beats out the zoom at f/8. The results are pretty similar, but the prime still wins. The issue isn't one of designing wide primes being more difficult than wide zooms. It's that it's more difficult to create an f/1.4 wide angle lens than it is f/2, f/2.8, or f/4.
    I generally use the 24/1.4 on a 1.3x crop. I'm happy. I'm even happy when I use the 24 on a full frame. I rarely notice vignetting, even wide open. Why? I'm shooting at f/1.4 when there's virtually no light. So there's not that much light around the outside of the frame, anyway. :)
    Eric
     
  15. "My line of thinking is that people usually buy fast lenses (2.8 and faster) in order to use this fast aperture most of the time."​
    They most certainly will, after all that's what they paid the extra cash for.
    But only newcomers would attempt to shoot planar subjects like a fresco with a wide-open aperture and later complain about vignetting and soft corners.
     
  16. I wonder why it is more difficult to design a fast aperture prime than a slower (but still fast) zoom. Look at the results of the 70-200/2.8 IS II.​
    That's not a very fair comparison. A telephoto is much easier to design than a wide angle, by virtue of the fact that the light rays have to be bend much more for the wire-angle.
    Compare the 70-200 to the 135L and I have no doubt the 135 will win.
    Similarily, compare the 24L to the 16-35L, and suddenly the corner resolution of the 24 might seem much more favourable. (especially at similar apertures, the 24 is pretty damn good by f2.8)
    If you want perfect corners, you might consider the 24 TS-E...
     
  17. Well, I use the 24 L MKII for (among other things) landscape shots with the night sky included. One of the advantages of having a f/1.4 lens is that by the time that you stop down a couple of stops (say to f/2.8), the lens is already at its "peak". At f/2.8 and ISO 400/800, I can shoot 20 or 30 second exposures with excellent results.
    If I were using a f/2.8 lens, I would have to stop down to f/5.6, and up the ISO concurrently, to get the same thing. Not feasible.
    Is the lens soft in the corners at f/1.4? Yes it is, but that is physics and lens design compromises.
    00WUDI-244987584.jpg
     
  18. Is the lens soft in the corners at f/1.4? Yes it is, but that is physics and lens design compromises.​
    I guessed so. :-(
    Happy shooting,
    Yakim.
     
  19. But if it's 'just physics', why is the Nikon 24 f/1.4 at f/1.4 (image taken from Ken Rockwell's review):
    [​IMG]
    ... so much better than the Canon 24 f/1.4 at f/1.4 (taken from Lens Tip review):
    [​IMG]
    Here's another comparison. The Nikon seems to murder the Canon.
    Does anyone here have any hands-on experience with the two lenses?
    Cheers,
    Rishi
     

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