Blurry photo again

Discussion in 'Beginner Questions' started by jiwooseok, Sep 21, 2020.

  1. I would say with a lens of this size, a tripod always helps. At least you don't have to hold all that equipment with your muscles.

    I agree that the picture is sharp, but noisy, and the focus is not completely where I would want it to be. Focusing on anything at f/1.4 is a challenge, and at the resolution of the D850 and such shallow depth of fields, I would not consider a person stationary by any means, even if they tried to stay in one spot. Just breathing normally will produce enough movement that things will move out of focus. So 1/60s shutter speed would be too slow too, even from a tripod, unless you really are photographing a steady subject, which, as we established, a human being is not. That being said, I think you could get away with around 1/250 or so, allowing you to drop the ISO a few stops, reducing the noise on the final image. Getting more light and stopping down slightly would help even more.
  2. William Michael

    William Michael Moderator Staff Member

    Whilst of some interest agreed; the spend is not the main point.

    I think the salient points are, thus far:
    > the OP has been USING the gear and then
    > asking relevant "beginner" questions
    > moreover seems to be reading and understanding the responses.

    stuart_pratt likes this.
  3. If you go from 1/60th to a 250th you’ll need to UP the ISO, not drop it, unless I’m not understanding your point? I’m not sure I follow what influence the shutter speed has on the ability of the camera to focus accurately? We’re not talking motion blur here. OK, the person might be swaying very slightly by breathing, but I don’t see how upping the shutter speed will help nail the focus?
  4. As previously explained: Mains powered artificial light flickers at twice the mains AC frequency. Therefore any shutter speed shorter than that flicker frequency will give a variable exposure, due to only part of the cycle being captured.

    1/60th will be fine, unless the subject is really fidgeting about.

    However, the real answer is a smaller aperture and more light. Forget the razor-thin depth-of-field and 'bokeh' that only impresses other photographers. Get the face sharp all over! Or at least enough DoF to cover the nose to ears.
  5. The picture was taken at 1/1250s. 1/250s would reduce the ISO compared to that, but you're right, not as much as 1/60s would.

    Indeed, motion blur is not a problem in the original image that was taken at a shutter speed of 1/1250s. I am implying that it might be at 1/60s.

    I was simply trying to say that using a longer shutter speed was a good idea, but I wouldn't go as far as 1/60s, because that might introduce new problems.
    Last edited: Sep 26, 2020
  6. William Michael

    William Michael Moderator Staff Member

    The type of lighting is relevant too. The original was taken with (assumed) a mains powered light "a regular light for a test on a tripod"

    And I think we've established that the very shallow DoF (about 4mm) and the high ISO combine in a result which the OP is terming "blurry", plus, it is likely that the OP did not nail focus on exactly the part of the eye intended. Also micro focus lens adjustments might be necessary

    As rodeo joe points out, when using mains powered lights the flicker rate needs to be considered.

    If the OP wants to make Portraits like the example, then using Flash as the main lighting source would be a good option; using a smaller aperture than F1/4 would be a useful approach; and a lower ISO would reduce the noise. Flash lighting also would arguably eliminate Subject Motion Blur, and, with a quick reaction time on the shutter, assist in nailing the shot "as focused".
  7. William Michael

    William Michael Moderator Staff Member

    On a technical point of Shutter Speed only, disregarding all other considerations.

    For mostly all of my Portraiture for the last 20 years, I have used only Available Light. For tight shots, for example Half Shot to a Tight Head Shot, I would always be pulling 1/125s or faster, preferably 1/250s, for an healthy and composed adult, standing. Any slower shutter speed was/is too dangerous in respect of capturing Subject Motion Blur in the face region.

  8. Do we really need to complicate things (at this stage) by introducing speedlights and avoiding the awful lighting got from on-camera flash?

    1/125th @ f/4 and 100 ~ 200 ISO should be easily doable with the sitter next to a window in reasonable daylight. And side window light can be very beautiful and flattering.

    It's overcast and dull today here, and I'm still getting 1/125th @ f/2 for 100 ISO at 1 metre from a south-facing window.
    Last edited: Sep 26, 2020
  9. On aperture, I tend to aim for a depth of field of at least 20-30cm when shooting portraits, that will give an aperture of f4 or f5.6 with most common portrait lenses.

    Obviously, if light levels are low, I'll open up and accept a softer result (I do like my fast lenses), but if you want nose to ears to be sharp and still defocus the background, f4 is a good starting point.

    The 'classic' rangefinder portrait lens was a 105/3.5 or a 135/4, SLRs started to get faster as a brighter image made for easier focussing, monster lenses like your Sigma are a relatively recent thing. I find the depth of field on my 135/2.8 Pentacon to be thin enough that the slightest movement changes my point of focus.
    William Michael likes this.
  10. Agreed, and I apologize if my post seemed gratuitously critical. My point was that many newbies are misled into thinking that it's gear, rather than study and practice, that makes for a good photo, and they waste a lot of money and are very disappointed when the find out that this isn't true.

    I urge newbies not to spend a great deal because they won't know for a while which purchases might really help them and which will be simply a waste of money. For example, I realized at some point that the Canon f/4 70-200 would be BETTER for me than the f/2.8 that everyone raved about. I lug stuff on my old back, and I needed the lower weight (half) more than the extra stop. Saved me literally half the purchase price as well as the unneeded extra weight.
    NetR and William Michael like this.
  11. William Michael

    William Michael Moderator Staff Member

    I think that the example/suggestion was not complicating anything at all.

    The OP clearly states the example shot was "a test" for him/her being able to get non blurry photos. Clearly it has been explained to the OP that the image was not "blurry" in the sense that it was explained a sharp focus was, indeed, attained.

    Additionally, the commentaries have touched on and explained various matters, including but not limited to: Aperture relationship to DoF; Shutter Speed related to Subject Movement Blur; Mains Power Cycle Rates/Shutter Speeds related to Exposure (and Colour) differences; Micro Lens Adjustments; Live View Focusing. . . mentioning the use of Flash is no more complex nor simple than these points already mentioned

    Moreover the OP has the option to ask further questions should s/he not understand fully any general suggestion made in these commentaries.

    Au contraire to the position of limiting discussion of aspects which have a relevance to the Opening Post, (in this case arresting Subject Movement Blur in Portraiture), I think it is good to open the conversation, by introducing general aspects whereupon the OP can then choose to question and investigate, should they want to pursue any particular line of development and learning. In fact it could be seen as judgemental to assume that any OP is incapable of so doing.

  12. Those are high ideals William, but unfortunately we're not running a 3 year, hands-on photo course. Just responding to questions.

    I don't think anyone's making patronising assumptions about the OP's abilities. However, lighting is an entire subject in itself and do we really need to go off in that direction at this stage?

    The D850 doesn't have a built-in popup flash that could be used for a quick test. So the OP would need to buy a speedlight, and possibly get sidetracked from mastering basic camera-craft into the field of portrait lighting.
  13. William Michael

    William Michael Moderator Staff Member

    Yes, high ideals, agreed.

    I think that no one was being patronising.

    To be precise, I didn't think you were. I thought long and hard about that sentence before I published it and in so doing I considered your reaction to it: it was not meant directed to you.

    I answered you question as it was asked asked: I think that bringing the subject of Flash into the conversation is not an issue and probably beneficial. I further think that it is not a good idea to limit the conversation.

    You disagree with that view, and that's appropriate: your rationale has been clearly explained and certainly understood by myself.

    I apologize if you considered the tag of my last comment to be a personal barb, it was not, it was a general comment: your contributions are IMO, considered, valuable and based on much experience.

  14. Not always achieved but can be motivational and can supercharge action and creativity.

    "Realism is in the work when idealism is in the soul."
    Henri Bergson
    William Michael likes this.
  15. I think Joe's window light is rather better than mine was yesterday! Raining here in France though...

    Here is an example shot taken yesterday afternoon. Window light, 1/60th, F2.8, ISO 2000 on my Fuji XT2 with a 33mm f1.4 lens, which gives around the 30cm depth of field I mentioned in my post above. My house is too small to use a lens like your Sigma for a casual portrait, my 33mm is equivalent to a 50mm 'normal' lens on your Nikon.

    This is a 100% crop from a 'typical' portrait, head, shoulders and upper chest. Autofocus point was manually selected to be the eye, I can't really tell if it actually focussed on the eye, the glasses or the eyelashes, but it doesn't really matter as the depth of field takes care of it (I suspect it was the glasses rim, AF likes sharp edges).

    If I was trying to reproduce your shot from the first post, I would switch the camera to manual focus (and live view, on your camera) in order to position the point of focus exactly where I wanted it, but for the purpose of the shot I took, AF was fine.

    At f2.8, the background is still nicely defocussed, not completely obliterated, but pleasantly softened. I should have moved the electric cable!

    Detail is lost from shooting at a high ISO, as with your image, though not nearly to the extent seen in your shot. You might also want to look at the noise reduction settings on your camera, turn them down a couple of notches as noise reduction tends to obliterate fine detail.

    Example 100% crop, from RAW, no post processing other than darktable's 'standard' base curve, 33mm @ f2.8, ISO 2000, noise reduction set to -3 (very weak). DSCF7446.jpg

    Original shot, with my wife's permission, straight camera jpeg, no post processing. DSCF7446_01.jpg
    rodeo_joe|1 likes this.
  16. Good stuff Steve.
    A picture is worth a thousand words!
    I didn't. No apology necessary.
    William Michael likes this.
  17. William Michael

    William Michael Moderator Staff Member

    Last edited: Sep 27, 2020
  18. William Michael

    William Michael Moderator Staff Member

    I concur.

    Sometimes shallower DoF can be useful, but, 200mm to 300mm DoF is where I generally aim for, too. 200~300mm is about the 'thickness' of a person, and for a tight shot, such as the Tight Half Shot of your Wife, it works well.

  19. William Michael

    William Michael Moderator Staff Member

    Comment appreciated.

    The intent is always to encourage, nothing and more nothing less.

  20. William Michael

    William Michael Moderator Staff Member

    I concur.


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