Maximum Acceptable ISO for Wedding Portraits?

Discussion in 'Wedding and Event' started by david_l._forney, Feb 1, 2010.

  1. At what point is ISO unacceptably high for producing high quality enlarged wedding portrait prints (say 13 x 19)? David
     
  2. Which camera are you asking about? ISO behaviour varies quite widely.
     
  3. Since you said 'portrait', I would say it also depends on how you processed the image, how you exposed it and possibly, what the circumstances were at the time you shot the portrait. Also, who is doing the accepting or rejecting--you or the client?
     
  4. For portraits you're typically looking at 100-400, however this can vary with lighting and other variables. Also, how you define "acceptable" can vary from person to person. The portraits that I do at a backdrop with my portable lighting are pretty much always set from 100-200, course YMMV.
     
  5. Sorry, this was part of a text which I deleted because it was too long. I am using a Canon 5D MKII full frame 24 megapixel camera. I'm having problems with getting good results with my Q Flash QFT5d-R because the shutter speeds are too low resulting in images that are not sharp enough (and the Q flash in both TTL and Auto mode overexpose the image). I shoot ISO 100 and am thinking of increasing to get a better stop action. Alternative would be for me to use manual mode and fix shutter, aperture and ISO and allow the Q Flash to make the right adjustment.
     
  6. This is an very subjective question. First of all, like Neil mentioned noise varies greatly on one camera to the next, also the amount of acceptable noise varies from one persons eye to the next. I personally shoot a Nikon D90 and was "told" by reviews that it held up very well at higher ISO's such as 1600 and 3200, but I don't agree that it's acceptable. In fact, I have an issue with the noise at ISO 800. I perceive noise very easily and it's only acceptable to me when it makes an artful impact. I personally wouldn't like a wedding portrait to be shot any higher than 800 if I were doing the shoot with my rig, unless the noise was meant to be done in an artful manner. Of course, at weddings there are times when a high ISO is needed, and I will use it to make sure I get the shot, but these shots are not what you would call "portraits" they are usually more candid shots, ones that the couple usually wouldn't bother enlarging bigger than 8x10 etc.
     
  7. The situations would be non-studio mobile shooting. "Acceptable" would be for me. I consider a portrait sharp if I can count clear, crisp hairs on the eyebrows when enlarged (which I can do when I get the shot right). I also shoot kids, so they move around quite a bit. Hence the problem of getting these types of shots using a flash. When I'm outdoors with good light, I can get the results I'm looking for. It's when I use the flash which is giving me the problems with children.
     
  8. I find with the 5D mk I, ISO 400 is exceptionally good (at least for landscapes) and I can only suspect that the 5D mk II is better (though not as good as the D3 if reviews can be believed). It's hard to believe that you wouldn't be safe with 200 or even 400. I guess I'll leave that to the experts to confirm.
     
  9. David, using a flash ought to make it easier to get these shots, not harder.
    I've never shot kids in a studio, but I've shot a lot of active models. This is my approach.
    Light is off-camera. Camera is on manual - 1/125, f11, ISO 50. Flash is positioned for correct attitude to model, wherever makes sense for the lighting ratio I want. Power on flash unit is adjusted until it reads f11 with a flash meter. If it's not powerful enough then I may use a more moderate aperture - say f8 or f5.6. The camera aperture is always kept the same as the flash reading to prevent over-exposure.
    I can get detailed texture in hair, skin and eyes even when the model is leaping. The image is pin-sharp and totally frozen because f11 flash output is a powerful dose of light in about 1/10,000 of a second. It's the only thing that records on the sensor.
    No reason you can't do exactly the same with the Q flash. Just use it on manual.
    To answer the ISO element - for portraits I prefer to go as low as I can. But I'm happy up to 800.
     
  10. I guess I am confused by how you are shooting portraits. In my book, if it's a portrait, everything is in manual: camera & flash. When using flash, shutter is only relevant in regards to either maximum sync speed or how much ambient light you are letting in. Using a shutter of 1/30th vs 1/200th makes no difference on the flash exposure. Flash exposure is determined by flash power, aperture, and ISO. Sharpness will be a factor of lens quality and a fast enough shutter to freeze movement (and to a certain degree, flash duration). How fast that shutter is can be subjective. Again, slowing down the shutter doesn't mean you can use less (or more) flash power, it just mean more ambient light is striking the sensor. To break it down further, for full frame, I would be trying to shoot around f/8 for a group. I need that aperture for decent DoF. I might dial in my ISO for acceptable results. If I am shooting in a cave, in other words, very little if any ambient light, I might shoot ISO 1600. I know the noise is going to show up in the shadows, but the shadows will be in the background. My subjects will be properly exposed (thus reducing noise) by my flash. However, I try to stay below ISO 800. Then I dial in my flash power for my aperture (f/8) and my desired ISO. The shutter now only controls the background light. It has nothing to do with correct exposure of my subjects. My subjects should look the same at 1/30th or 1/200th- except for background separation. If I am getting motion blur, then I need a faster shutter and the background is what it is... or I need to light the background.
     
  11. Does this question have an answer? I don't think it does.
    The noise you get in a raw file is not simply and directly proportional to the ISO. There are other factors. I've taken photos at 1600 that were cleaner than photos taken at 1100 or even 800. I've shot (with a Pentax K20D with an APS-C sensor) photos at 1600 that seemed very nearly noise free. I've never been able to put the difference into words, but the quality of the light matters a lot, and other aspects of the exposure can matter too.
    Some noise looks like noise and is definitely objectionable. Some noise looks like film grain and can actually be attractive or appealing; some people think it adds atmosphere. Picasa and I think Lightroom 3 both provide features that allow you to ADD noise to images.
    Most images that look noisy on the computer print, especially at more normal sizes, with less apparent noise. And some images seem to be more amendable than others to clean-up with Noise Ninja, Neat Image or even the noise adjustments available in Lightroom or whatever. I've printed images taken at 1600 at 8"x10" and felt that they came out looking really nice. Just depends on the image.
    Finally, there's the matter of your hardware: the camera itself, the sensor, the in-camera noise processing feature, and the lens you're using. The amount (rather than the quality) of light you can get to the sensor makes a huge difference.
    For what it's worth, on my APS-C cameras, I try not to shoot over 1600. I generally use fast primes (I'm fond of my 28 f/1.7, 40 f/2.8, 50 f/1.4, 70 f/2.4, 85 f/1.4).
     
  12. Thank you all for your very helpful responses. To add information, I use only L series lenses and shoot 50% of the time with primes. I apologize that the question is dependent upon too many variables, and don't want to waste your time with theory. I initiated the question because I thought that boosting ISO would boost the shutter speed to help with the stop action for active children when I'm using a flash. I am simply not that adept at flash as I am with natural light. Neil, so you are saying that even though the curtain is open for 1/125 second, you get stop action because the only image recorded is from the 1/10,000 burst from the flash, even if the model is moving during the entire 1/125 exposure? Suppose you are looking for a narrower DOF?
     
  13. David - yes, flash output is controlled by aperture only. Shutter speed is irrelevant, except if you're using a camera with focal plane shutter when you have to shoot at sync speed or slower. And, given adequate flash power, you can stop any kind of motion, even at slow shutter speeds.
    If you want to use wider apertures you have to reduce flash power. This means dialling it down on the flash unit, or moving the flash further away from the subject. If you're using very wide apertures then you need to control the flash with some precision to ensure that you don't get too close to the correct ambient exposure. The closer you get to ambient exposure, the more subject motion will show in the image.
    Flash (in my opinion) is most easily used on manual as it's the only means by which you have total control. Otherwise you end up fighting with what the camera thinks you should be doing, which is invariably wrong.
     
  14. "I'm having problems with getting good results with my Q Flash QFT5d-R because the shutter speeds are too low resulting in images that are not sharp enough (and the Q flash in both TTL and Auto mode overexpose the image). Alternative would be for me to use manual mode and fix shutter, aperture and ISO and allow the Q Flash to make the right adjustment."
    If you are using an automated camera mode, I can see why you are getting blurred or ghosted images. Are you using aperture priority or AV mode? If you are, know that with Canon cameras, AV will always go for the 'correct' ambient exposure, even if you have a flash on the camera which is turned on. There is something called NEVEC, which operates on some Canon cameras, which underexposes the ambient (with a flash on camera that is turned on) in AV by a variable, but slight amount. Even if your camera has this behavior, it usually isn't enough to allow the flash to totally freeze subject motion (particularly kids).
    As Neil explains above, the closer you get to the ambient light in exposure, even with flash, the less you will be able to freeze subject motion purely with the flash duration. In addition, light, including flash, is additive. If you are using uncompensated or only slightly compensated AV, plus flash, you will get overexposure.
    Knowing the above, plus using your camera and flash the way you say in your second quoted statement is correct. The Q flash should be controllable, in both ETTL and auto thyristor, although the latter may not allow you to get as low in power as you might need if you are using the flash as fill only. In ETTL, you should be able to get pretty low.
    In addition, outside you run up against the maximum sync speed with 'regular' flash--1/200th shutter speed. With ETTL, you can use High Speed Sync but at the cost of power. The higher the shutter speed beyond 1/200th, the more power you 'lose'. Following kids around outside, you'll probably need to use higher shutter speeds because the shutter speed alone is probably what is needed to freeze motion (normally flash is fill only). Luckily you normally are pretty close to the kid, so HSS can probably be used. I don't think you can use HSS with auto thyristor mode.
     
  15. David, several people have tried to help with this question, but are you honestly going to pick what you think is the best answer and then gamble a portion of your next paying gig (and your reputation) on that answer? Here's a better idea;
    Take some family/friends who will act as 'models' to a situation of lighting, space, etc. similar to that in which you anticipate the need for higher ISO. Experiment and practice with higher ISO's until you find out what the threshold is for you, your equipment, your software, and workflow to produce what you feel are acceptable images. No more guessing, no more gambling on whose answer fits you best.
    This is not to take anything away from any of the responders above, probably all of whom are much (!) more experienced than me. It's just that another photographer can only answer a question like this in terms of what works for him or her.
     
  16. I agree completely, Jim, about using what works for oneself and testing things out for oneself. However, it appears to me that David isn't understanding a couple of concepts fully, which leads him to conclude that he needs higher ISOs to solve a blurring problem. Using higher ISOs, again--to me--won't necessarily solve the problem.
     
  17. William Michael

    William Michael Moderator Staff Member

    "At what point is ISO unacceptably high for producing high quality enlarged wedding portrait prints (say 13 x 19)? [regarding Flash Exposure]"
    I have only glance read the responses, and I also typically would use Manual Flash and a Flash Meter in an ad hoc studio setting for Portraits shot under Location Flash.
    On point which I don't think has been covered, is that you do need to get the exposure correct and the penalty for underexposure could be interpreted as poor ISO performance.
    So my suggestion if you are going this “manual” route - get a good comprehensive Light / Flash meter and learn how to use it.
    I have a 5D and will comfortably use it up to and including ISO400 with Flash to go to 11 x 14 Full Frame Crop for Portraits.
    WW
     
  18. Thanks to all for your input. The collection of comments have given me some good ideas for exploring solutions. Thank you so much again. David
     
  19. david - not sure what other people are saying. on a 5D, 1600 is the highest I would comfortably go.
    on a 5d mark 2, 3200, no problem.
    ce
     
  20. 400 (rated at 320 with film) is the fastest I would go.


    Learn to use a flash, no need to really go higher.


    I don't get this prolific available-light BS. For certain situations, yes, it becomes a necessity, but available light is seldom, if ever flattering.

    Only use available light, and the high ISO it entails if it is YOUR available light ;-)



    The maybe, one exception I would consider is shooting in available light in a church. The warm tungsten look, uncorrected, is quite beautiful in some locations, although, I notice you may not want to have a digital camera set at regular daylight setting, maybe warm it up a bit or else colors can get too ruddy.
    Even here, with a fast enough lens you can hand-hold this in most churches.
     
  21. I'd encourage you to check-out Will Crockett at SHOOTSMARTER.COM. He has some excellent camera/lighting info that speaks directly to your question, especially with the use of Quantum equipment. Much of what you'll need is FREE, but his DVDs are worth the investment (should you be interested).
    Richard
     
  22. Maximum acceptable amount of green in a winter picture? The OQ is quite scarry....
     

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