Peter_in_PA Posted September 22, 2008 Share Posted September 22, 2008 That image looked in focus from front to back, but what about zooming in, as if I were printing much bigger than just a 4 x 6. Now, here is a 100% pixel detail from the spot I focused on, at various f-stops. You can clearly see here how diffraction starts to set in at f22 (much better than some other lenses I have, which seem to start to suffer at f16), and how it is noticeably softening the image at f32. No doubt, if I were printing big, this would create a problem for me.<div></div> Link to comment Share on other sites More sharing options...
jerry_schuler Posted September 22, 2008 Author Share Posted September 22, 2008 Peter, The F2 club will kick you out unless you show a F2 (or there abouts) photo of your car. Link to comment Share on other sites More sharing options...
patrick j dempsey Posted September 22, 2008 Share Posted September 22, 2008 It occurs to me that the reason that ignorance and stubborness are so commonly found together is that people will simply not allow themselves to learn anything. You are obviously connected to the internet, so you obviously have access to the largest free library of information ever assembled by man, and getting larger every day. But instead of looking it up yourself, you ask the question on a forum and then attack the people who give you the correct answer, simply because you refuse to hear the correct answer. Diffraction is not like Murphy's Law or the Rule of Thirds or the Rules of Etiquette. It is not an arbitrary law that was made up just to make some people mad. It's physics. Light acts as a wave. When a wave of light passes through a small hole and strikes a surface, the pattern of the wave can become visible. This is what diffraction is... the appearance of an image being out of focus because of the pattern of waves striking the surface are not organized. The size of the hole, the distance from the hole to the surface, and the relative size of the image to the wavelength of the light are the determining factors in whether or not the waves will be disorganized and create diffraction. It just so happens that the size of the hole and the distance from the hole to the surface is contained within the ratio called the f-stop. The f-stop is the focal length of the lens divided by the diameter of the aperture opening. Because f-stop contains the focal length of the lens in it's calculation, lenses of different focal lengths on the same format do not act differently in terms of diffraction. A 12mm lens has the same diffraction limit as a 600mm lens, but the difference will be in the amount of DOF in relation to the subject distance. The relative size of the image to the wavelength is expressed though the format of the film or sensor and it's resolution. The smaller the sensor is, the more magnification is required to view the image, and the greater the resolution of the sensor, the more magnification is possible. Adams shot on an 8x10 view camera. An 8x10 negative has over 100 times the area of a 35mm negative, which means it has over 200 times the area of an APS-C sensor. That means that even at the diffraction limit for 8x10, one of his negatives could be blown up 200 times larger than an image from an APS-C sensor before showing softness from diffraction. (Film resolution vs. pixel resolution not withstanding). Another case is that a 6MP APS-C sensor will not resolve diffraction until it becomes very bad simply because the sensor sites are larger than the disorganized light waves. But a 12MP APS-C sensor will resolve more diffraction at a lower aperture. This means that small-sensor digital cameras have a resolution limit imposed by diffraction. Here's a rule of thumb, see how it works for you... if the best sharpness for 8x10 is at f/64, then for 4x5 it's probably f/45, for larger medium format it's probably f/32, for 645 it's probably f/22, for 35mm it's around f/16, for APS-C or half-frame 35mm it's f/11, for 4/3's it's about f/8. You will notice that most camera designers don't want you to use your camera beyond it's diffraction limitations, so lenses are usually limited to 1 or 2 stops past the best resolution. The problem is that if you are using a Canon or Nikon dSLR with a lens designed for a film or full-frame sensor, it might have settings 3 or even 4 stops beyond the sharpest setting... because it is designed for a different format with a different diffraction limit. Link to comment Share on other sites More sharing options...
jerry_schuler Posted September 22, 2008 Author Share Posted September 22, 2008 Despite all your arguments and learnedness, it's evident that good photos can be achieved at higher F/stops. It’s insane, “LOOK AT THAT PHOTO. IT’S F32 AND OK. YOU OBVIOUSLY DID NOT LISTEN TO WHAT I SAID!” Link to comment Share on other sites More sharing options...
garry edwards Posted September 22, 2008 Share Posted September 22, 2008 Back to my original thought - this guy cannot believe what he's saying - he MUST be trolling... Link to comment Share on other sites More sharing options...
Peter_in_PA Posted September 22, 2008 Share Posted September 22, 2008 Jerry, Again, I showed you, based on what I've learned about that lens, a best case scenario. f32 is clearly "ok" but not "best". Therefore, i would not choose f32 for my image if I wanted the best image. Ansel and his buddies in the f64 club were looking for what was best, not what was ok. Here's another example, my Tokina 11-16, which goes from f2.8 only to f22 (wisely, they don't bother letting this very wide lens step down further than that. You can, again, see the diffraction set in past f11. I have learned that best results with this lens are found at f5.6 or f8, and at the wide end, there's so much in focus that those f-stops work great. I have only gone to f16 a couple times, and probably didn't need to.<div></div> Link to comment Share on other sites More sharing options...
Peter_in_PA Posted September 22, 2008 Share Posted September 22, 2008 And yes, Garry, I know. I'm doing this more for the benefit of someone else in the future. Link to comment Share on other sites More sharing options...
jerry_schuler Posted September 22, 2008 Author Share Posted September 22, 2008 Thank you peter. I'm satisfied with OK as long as other look at say "It's OK." I do not think I've ever managed the best in anything. Part of my career was over 15 years in quality assurance. OK is what we always worked for. Best is phenomenally expensive like the Ford's three million dollar Superchief pick-up truck. And still people said it was not the best. The F2 club still need to see that F2 (or there abouts) picture of your PEZ car not just a crop. Link to comment Share on other sites More sharing options...
Peter_in_PA Posted September 22, 2008 Share Posted September 22, 2008 btw, Jerry, I just noticed you've been asking similar questions for months, now. Have you invested in any of the better books on photography yet? They would be quite helpful! "Understanding Exposure" is great, and I think "The Camera" by Ansel Adams will explain a lot of the questions you've asked, too. Good luck! Link to comment Share on other sites More sharing options...
jerry_schuler Posted September 22, 2008 Author Share Posted September 22, 2008 That sounds like a no on the F2 club picture. Link to comment Share on other sites More sharing options...
photo_dark Posted September 22, 2008 Share Posted September 22, 2008 The bottom line is that if you are convinced you can take better pictures at F32, then you should do it. No one is going to stop you. Just realize that no one is likely to join you in your quest for.... images taken at F32. Link to comment Share on other sites More sharing options...
waltflanagan Posted September 22, 2008 Share Posted September 22, 2008 Please take your medication. Link to comment Share on other sites More sharing options...
Peter_in_PA Posted September 22, 2008 Share Posted September 22, 2008 Jerry writes [That sounds like a no on the F2 club picture.] LOL. Nope, neither one of those lenses goes to F2. I LOVE f2 on my 50mm f1.8 though... for some things. Link to comment Share on other sites More sharing options...
joseph_wisniewski Posted September 22, 2008 Share Posted September 22, 2008 "I didn't need to use trial and error to know that firing at unbreakable targets was a waste of lead." Would you have changed your choke if you had not seen the other shooters fail to break? Would you have done it if you had been first and had not seen where the clay appeared? It took trial and error for these things to come to light. You just had a golden opportunity (and you took it) to learn from someone else's trial and error. Link to comment Share on other sites More sharing options...
joseph_wisniewski Posted September 22, 2008 Share Posted September 22, 2008 Jerry, there's no conflict here. You started this thread by talking about how impressed you were with Ansel Adams. Adams wasn't about "good enough" on a low res web image. He was about images looking "stunning" on a 16x20 B&W print. As was the rest of the f64 group. Your f32 images on a crop sensor DSLR will not look good on a 16x20 print, or even an 8x10. They will look soft. If you want to "be Ansel", you've got to take the kind of care that he did.There's an old saying: the enemy of "great" is not "poor". The enemy of "great" is "good enough". Link to comment Share on other sites More sharing options...
jerry_schuler Posted September 22, 2008 Author Share Posted September 22, 2008 Joseph, The actual truth is that I was trying to placate Peter Hamm before I had to go in the attic and get my HP 2800 wide format printer and mail him a copy of a photo on 13 x 19 inch stock through the US postal service. Link to comment Share on other sites More sharing options...
JDMvW Posted September 23, 2008 Share Posted September 23, 2008 This is postmodernism taken to a new level. While we're at it why don't we make the value of pi be 3.0 so that it won't be so hard to calculate formulae? Moreover, there's biblical evidence that pi is three (First Kings, Chapter 7). Link to comment Share on other sites More sharing options...
patrick j dempsey Posted September 23, 2008 Share Posted September 23, 2008 3 pi's for the price of 3.1415926535897932! Link to comment Share on other sites More sharing options...
danielleetaylor Posted September 23, 2008 Share Posted September 23, 2008 <P><i>Therefore, i would not choose f32 for my image if I wanted the best image.</i></P> <P></P> <P>What is "best" varies from image to image. Sometimes "best" means maximum DoF even if that means a bit of diffraction. </P> <P></P> <P>Attached are the f/5.6 and f/22 samples you made using your 11-16 with one change: USM was applied to the f/22 sample 120/1/0.</P> <P></P> <P>Yes I know USM can't add detail that is lost. Yes diffraction will in some cases cost fine detail that cannot be restored through USM. Never the less, too much is made of this "rule" about usable aperture range. Certainly it's good to know hyperfocal distances and use them to stay within optimum apertures where possible. But if you need the DoF, stop down and adjust your USM settings in post.</P><div></div> Link to comment Share on other sites More sharing options...
garry edwards Posted September 23, 2008 Share Posted September 23, 2008 *Joseph Wisniewski . "I didn't need to use trial and error to know that firing at unbreakable targets was a waste of lead." Would you have changed your choke if you had not seen the other shooters fail to break? Would you have done it if you had been first and had not seen where the clay appeared? * Fair question, I think that I used my technical knowledge to work out that the shot pattern with a skeet choke would fail and didn't need to see that other people were failing to do so. It was obvious. The first person to shoot isn't at a real disadvantage because the first shooter is 'shown a pair' from the shooting position. However, if I had been the first to shoot I probably wouldn't have had (or taken) the time to do the sums. That problem doesn't obtain when photographing a chess board, there's plenty of time to do the sums, work at the angles and apply the theory. Theoretical knowledge isn't always a complete substitute for trial and error but I do believe that an understanding of the process, and an understanding of the underlying physics, makes most trial and error redundant. Second hand knowledge is rarely a good substitute for real understanding, as evidenced in both the original question and several of the answers Link to comment Share on other sites More sharing options...
Peter_in_PA Posted September 23, 2008 Share Posted September 23, 2008 Daniel, At last... a great, intelligent response. Yes, this is true, however with that particular lens, I have so much depth of field at f8 and f11 (and at 11mm, f5.6) that I may as well use the "sweet spot" and get all I can in terms of detail so that USM has loads to deal with. You are so right, it is a general rule and can be broken (indeed, with my micro I break it all the time), but the original post was about Ansel's amazing clarity and depth of field, and presumably about how to emulate that (short of using a larger format). I maintain that if you know you are going to print a big "art print" you should use the best setting on capture you possibly can. If I was shooting with a 35mm or 55mm lens, I could definitely see a situation where I might very readily "break the rule" as you say, but not with a wider lens. Jerry writes "Joseph, The actual truth is that I was trying to placate Peter Hamm before I had to go in the attic and get my HP 2800 wide format printer and mail him a copy of a photo on 13 x 19 inch stock through the US postal service." Aha! Your true colors are showing, Jerry. I'm wondering if you have actually learned anything here. Doesn't look like it to me. Oh, well... We tried. Link to comment Share on other sites More sharing options...
danielleetaylor Posted September 23, 2008 Share Posted September 23, 2008 Peter, I think we're in agreement. I wanted to address this issue simply because some posts make it sound like one can never shoot smaller apertures. I've met people who treat this as a hard and fast rule which is never to be broken. I didn't mean to pick on your posts in particular, but you had sample images I could use to illustrate my point :-) Link to comment Share on other sites More sharing options...
kristina_kraft Posted September 23, 2008 Share Posted September 23, 2008 Jerry, I used to photograph often on f/22, using slides 36x24mm. I found that it is good for the images of blue sky and clouds. F732 and F/36 might be good to get really deep blue sky but only when the sky is clean without a haze. It's the same for the sunrise or sundown. The colors might be more saturated. In that way the diffraction might be invisible. The focus is on the colors and tones, not on the objects. So, you might try this. Link to comment Share on other sites More sharing options...
Ed_Ingold Posted September 23, 2008 Share Posted September 23, 2008 Jerry, <p> <i>Despite all your arguments and learnedness, it's evident that good photos can be achieved at higher F/stops. It’s insane, “LOOK AT THAT PHOTO. IT’S F32 AND OK. YOU OBVIOUSLY DID NOT LISTEN TO WHAT I SAID!”</i> <p> What a stunning example to prove your point. What is it, 500 pixels wide at 96 ppi? I was mislead into thinking we were talking about prints 16x24 inches and up at 300 ppi. <p> As Joseph said, the only reason to respond to this thread is for the edification of those who are curious and willing to learn. You will not be pursuaded and there's no point in trying. It's like wrestling with a pig - you get muddy and the pig loves it :-) Link to comment Share on other sites More sharing options...
Peter_in_PA Posted September 24, 2008 Share Posted September 24, 2008 Jerry is only looking for an "OK" image after all. For those of you looking for OK 4 x 6, 5 x 7, or on-screen viewing, stop all the way down, you'll probably be happy. For those of us looking for the best possible image... learn your lens(es) and shoot carefully... or... if you don't have time... "f8 and be there." Link to comment Share on other sites More sharing options...
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