50mm f1.8 tips

Discussion in 'Canon EOS' started by robert_g.|2, Dec 3, 2009.

  1. I just got the 50mm f1.8 prime lens today for my Rebel T1i. I seem to have trouble getting focused shots, especially when using f1.8. Any tips for me? I've tried all kinds of lighting (indoor, outdoor, inside w/flash on tripod, flash inside handheld, etc) and the majority seem out of focus for almost the entire picture. Any tips? Thanks.
     
  2. You are going to have a pretty small depth of focus at 1.8. Your focusing will need to be rather precise. Trying it at smaller apertures will you more latitude for mistakes in focusing. JR
     
  3. I think there is something probably wrong with your lens do you have any samples.
     
  4. Yup... if you're shooting it wide open at f/1.8, and focusing on anything fairly close to you, you'll see very little actually in focus. You can see exactly how much wiggle room you have by trying different distance/aperture recipes in this depth of field calculator.
     
  5. I have received great advice from people on this site about the same thing with the same lens. I would suggest you get a depth of feild calc and try messing with the settings for the lens. It really opened my eyes to how little room you have to work with in terms of DOF.
    Another tip is to be careful with focus and recompose as the plane of focus changes and is so narrow that you can easily mess it up.
    cheers,
    Andrew
     
  6. I was mostly shooting at f1.8 so I will try some smaller apertures and hopefully there will be more in focus. I will keep you focused. Thanks! Any further tips would be great. Also, if any of you have pictures online that you've taken with this camera please give me the links so that I will be INSPIRED! :)
    Here's a sample of my crappy shots. See how NOTHING is in focus?
    00VAUb-197627784.jpg
     
  7. what was your shutter speed? that could be camera shake. JR
     
  8. Indeed - that looks more like motion blur.
     
  9. Focal length: 50
    F number: 2
    Exposure time: 1/50
    I was holding the camera pretty steady. Maybe I should've make my f-stop in the 4 range?
     
  10. what is the ISO? if it is low then boost it, close the aperture, bump the speed.
    it's not ideal to shoot with f1.8 or f2.0 for the result you want (like whole thing in focus).
     
  11. Here's more info...
    Shooting Mode Program AE
    Tv( Shutter Speed ) 1/50
    Av( Aperture Value ) 2.0
    Metering Mode Evaluative Metering
    Exposure Compensation 0
    ISO Speed 320
    Auto ISO Speed ON
    Lens EF50mm f/1.8 II
    Focal Length 50.0mm
    Image Size 3456x2304
    Image Quality Fine
    Flash Off
    FE lock OFF
    White Balance Mode Auto
    AF Mode AI Focus AF
    Picture Style Standard
    Sharpness 3
    Contrast 0
    Saturation 0
    Color tone 0
    Color Space sRGB
    Long exposure noise reduction 0:Off
    High ISO speed noise reduction 0:Standard
    Highlight tone priority 0:Disable
    Auto Lighting Optimizer 0:Standard
    Peripheral illumination correction Disable
     
  12. Try 1/100 speed or faster, increase the ISO , or get more light.
     
  13. It might be motion blur, but 1/50 is not very slow on the 50mm (80mm). Was that shot with a tripod?
    Is the Auto-focus engaging? Do you hear the motor going when you half-press?
    (Might want to double-check the AF-MF switch on the lens)
     
  14. Hand held.
    AF Mode AI Focus AF
    Shooting Mode Program AE
    Mars I will try to keep that in mind. But, shouldn't P mode take care of that for me for the most part? 1/50 seems pretty fast.
     
  15. Spearhead

    Spearhead Moderator

    It's not that fast if you're not doing a lot of shooting at that kind of speed. Put the camera on a tripod, try a shot. If it's in focus, it's your technique. If it's out of focus, it's your lens. But there is no reason to believe that shot's problem is anything but technique.
     
  16. I love my little 50. I agree this is eiher camera shake or you lens has an issue.
    1. When I am at 1.8 I am always using manual focus.
    2. Using a 5D2 I use Live view to zoom in to verify focus.
    3. I use single shot focus mode not AI focus for still shots.
    Here is a 50 1.8 sample. http://www.photo.net/photo/9430015
     
  17. My 50/1.8 is fine in AF. 1/50s is too slow for sharp handheld shots unless luck is on your side.
     
  18. My copy of the 50mm f/1.8 II was just fine (as have all other copies I have seen and borrowed from other photogs) with regards to AF and IQ at f/1.8. Pick single point focus and use the center focus point and make sure it hits your subject.
    Practice a whole bunch!
     
  19. Mars I will try to keep that in mind. But, shouldn't P mode take care of that for me for the most part? 1/50 seems pretty fast.​
    Program mode is OK but it doesn't always get it right. For full frame cameras you should generally use a shutter speed that is 1/(focal length). For a 50mm that is 1/50 of a second. However you are using APS-C sensor that is smaller than a full frame. That changes the formula to shutter speed = 1/ (focal lenght x 1.6). So with a 50mm lens you should use a shutter speed of 1/80 or higher. Personnally I would aim for greater than 1/100 for best results.
    And as others have suggested stopping down the lens would increase depth of field which is probably what you want. Taking the higher shutter speed needed plus stopping down the lens to increase depth of field you would probably have needed an iso of 2560 (+3 stops for an exposure of 1/100 at F4). If you don't want to use a iso setting that high you would probably need a flash or use a tripod.
    Other than camera shake you might have accidently focused on something other than what you wanted or the lens might have a focusing problem. To verify the lens is focusing correctly you should do a focus test.
     
  20. If you have a steady hand or a support then 1/30 should be pretty usable unless you zoom in to 100%.
    My results at 1/50 using a XTi/400D are always better than the sample shown.
    A sample of 1/25 while wobbling crouched in the rain.
    Also crouched, 1/50 sample .
    (O.K. sometimes at miss at low speeds ... a 1/30 sample also in the rain shot while slowly walking by.)
    (O.K. one more as a sample of what it can do . 1/160, F3.2, ISO 400.)
     
  21. I love this lens. I had some problems getting used to it, but once you do it's well worth it.
    At 1.8 you really don't have much margin for error. 1/50 is maybe a little on the slow side.
    Have you tried changing your camera setting to a 1-point focus setting instead of 9-point, you focus that point on what you want sharp and then keeping the shutter pressed you recompose and press the shutter?
     
  22. Your tips are awesome. Thanks to ALL of you. I am going to try to change it to center focus and increase the shutter speed (and iso if necessary) and I will test out the results.
     
  23. Here's a couple of samples to show you how shallow depth of field gets (handheld). I sometimes find it's easier to switch to manual at wide aperture, especially if the subject is close, and focus by moving myself and the camera back and forth.
    1.8 @ 1/160, ISO 1600
    2.8 @ 1/20, ISO 400
     
  24. To test the lens, go outside when the Sun is shining and take a picture using a really fast shutter speed, like 1/1000. Find a subject with good contrast, to help the autofocus mechanism. If that photo is blurry, you can take a photo of a slanted yardstick to find out if the lens is focusing too near or too far.
     
  25. Further support of above comments:
    1/50 sec is beyond many people's ability to hold things steady
    f/1.8 or f/2 is going to have a very shallow depth of field. In this situation, too, any swing and sway on the part of the photographer is going to affect things more in making it hard for the AF to settle on something.
    Especially, since (although the above picture does't load for me for some reason) autofocus on any lens in any situation simply has little way to know which of the almost infinite number of possible things should be in focus. That's why macro photography is usually better done with manual focus than with AF. What is amazing is how often the AF does get it right. You need to pay attention to which of the little squares is lighting up....
     
  26. In addition to what everyone has written, I also suggest focusing on ears or other contrasty lines. If he had a music holder close to his head, I'd use that. In my experience, eyes can be difficult for lenses to stay on (but of course eyes are usually what you most want in focus.)
     
  27. I think thats your slight movement thats blurring the image. Sometimes you think you're holding steady, but the camera proves you wrong. Test your lens by either using a tripod or shooting at a higher speed (even if it turns out underexposed). If the image turns out to be sharp, then error was you in that pic. If the image still isn't sharp somewhere in the image, maybe its your lens.
    As stated, remember depth of field is shallow at 1.8.
    On a 50mm lens at 1.8, at a distance of 10 feet, your depth of field is only .81 feet; at a distance of 20 feet, it increases to 3.3 feet.
    http://www.dofmaster.com/dofjs.html
     
  28. So at those settings if I'm 10 feet away from the dude there should be .81 feet worth of "in focus" subject right?
     
  29. Right. Under one foot is right. And if he's moving, and you're moving, even by a couple of inches as you focus/compose, you might have your critical focus point drift a combined several inches forward or backward in that under-10-inch zone, which might leave you with just a few inches of workable DoF. Gotta have a plan, when you're working with that critical a slice of the scene.
     
  30. If your subject is moving at all, try servo mode.
     
  31. umm weird!
    i guess im the lower case andrew Robertson! lol
     
  32. Hahahahahaha...
     
  33. I think quite a few copies of the 50 1.8 are not very sharp wide open, my copy is one of them. I don't really try and use it below 2.0 or 2.2. At 1.8 it may look ok when the picture is small size but if you look at it full screen not even 100% you can see the softness in the middle (and gets worse the further from the middle) and its not due to focus. It is the lens, If you do some research you will see the same thing in other places. Some of them are better than others so If you really want to shoot at 1.8 you will prob just have to get a few diff copies and keep the best one.
    Do keep in mind that on a crop body your 50mm is around 80mm so you need to up your shutter speed accordingly like the others said.
     
  34. To me, the first pic suggests it's not a motion blur or shaky hands. It's more like out of focus (front focus to specific). I suspect the focus is somewhere between the saxophone man and you. Try to quick shot 3 simple objects arranged diagonally towards the camera, e.g. 3 batteries, and see where's the focus.
    I have this lens (mk II, and now mk-I) and this is a good lens. Of course it's rather soft and less contrast wide open, but it's OK if you print it small-medium size. At 2.8 this lens is sharp with a good resolution.
    You should also try to shoot with other lenses. If the problem persists, it could be your camera which is misfocused.
     
  35. I have also had similar issues. I do find the focus on that lens to be somewhat unreliable - when it is off it is usually front-focusing noticeably until f/4. This issue was noted in the dpreview review of this lens. I usually increase the number of shots I take in order to compensate for this, or if I'm in a situation that allows it, I will use manual focus with magnified live view. That said, I do much of my shooting with this lens at apertures f/2.8 and smaller so it hasn't been a huge issue for me.
    Additionally I have found that I prefer the increased overall image contrast at f/2.2-f/2.8 (vs wide open) and will almost always use higher ISOs up to 1600 in order to get there. This is a matter of personal preference - I am not a stickler for noise, as I have yet to make a print where it was noticeable at a normal viewing distance.
     
  36. Also, by my judgment the main problem in your sample photo is front focusing - motion blur may be a secondary issue - if I were taking that photo I would shoot for around 1/80 or so.
     
  37. Hello
    It looks like camera motion to me. Considering the shutter speed it is a likely candidate. I often see people holding their camera steady, then stabbing the shutter release button like a Roman Senator visiting Julious Caesar.
    Slow and gentle, you should not feel the transition.
    An old rule of thumb for anyone is to expect only sharp images with the focal length as the speed. I suggest for many to double this, and only expect it with practice. Since the 50 is an 80 on your camera I don't suggest you go slower than 1/80th
    All the other issues about focal plane being shallow have been mentioned and I agree with them. I can add one more thing. When I was testing my first EOS film camera (a 630) for AF accuracy [yes, this is indeed an old argument isn't it] I found that (using a ground glass on the film plane and a x30 Pentax microscope) that AF was in accurate compared to manual focus. This inaccuracy was absorbed by stopping down and at f5.6 was in detectable.
    The consensus at that time (on the thing called rec.photo) was that engineers were aiming at accuracy being at no more than 50lp/mm ... essentially enough. Modern digital cameras allow us to reveal better than we ever could on film the errors in focus. Perhaps that is a contribution to your issue also.
    I was never ever satisfied with my 20D and my EF50, however since going to a G1 and carefully focusing using the magnifier in live view (the camera is a permanent live view camera) my images using my 50mm are sharp and beatufiul. The following was hand held and is a resize not a crop. From an FD 50mm (which is a similar optic to the EF)
    [​IMG]
     
  38. I can offer you some tips here as I have used this lens extensively. First, make sure you set up your camera to only use the center focus point. This helps immensely in getting focus fast. This lens has a very rudimentary auto focus mechanism so it really hunts a while trying focus, and I found while only using the center point it seems to focus better.
    I use the aperture priority mode and let the camera figure out the shutter speeds. Here is what you can get when things go right:
    [​IMG]
     
  39. Thanks! Great picture. I will keep it on Av mode. Do you have a speedlite? If so, what setting was it on for this? High speed sync or normal?
     
  40. Hello.
    The same situation is valid for me. I have Rebel XS and 50mm f/1.8 II. I can not obtain pictures as clean and focused as the last poster Burhan's picture. I don't want to add my picture because i have the same situation with Robert.
    My question is that : How can i set/adjust shutter speed 1/80 or faster in Av Mode? I mean in Av Mode the machine will set shutter speed automatically regarding light conditions and we have no opportunity to determine this value?
    And if you think that my focus point is on the center where do i have to focus ; eyes or ears or elbows?
    Again regarding to light conditions do i have to set my XS Auto ISO?
    And the last one What is the ideal distance from the object to obtain not blurry images?
    Thank you very much,
     
  41. @Ali
    When using Av mode, you control the aperture and iso value, and let the camera handle the shutter speed. If you want faster shutter speeds in Av mode, either choose a larger aperture (smaller number) or increase the iso (higher value). If shutter speed is your main priority, choose Tv mode instead.

    Ideal distance - There is no such thing as one ideal distance for taking photos, but take a look at the DOF calculaters mentioned earlier in this thread, and understand how to use them. Also, take a look at http://www.photo.net/learn/basic-photo-tips/aperture-shutterspeed-iso/ for some introduction to basic exposure.
     

Share This Page