Blurry images while using my speed light

Discussion in 'Photography Beginners' Forum' started by vivienne forte, Nov 18, 2020.

  1. vivienne forte

    vivienne forte TPF Noob!

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    Hello everyone, Ive never posted on a forum before so please bare with me if i'm not doing this correctly but i really could do with some advise regarding a problem I encountered on the weekend.

    I used my speed light on top of my Nikon and unfortunately at least 50% of my photos are out of focus and i have no idea why. My shutter was set on 1/80th or above mostly 1/100. It was a very dark rainy /cloudy day so my iso was very high but i used shutter priority so it never went below 1/80. Could it be the lens i used ? a 50mm?

    Hopefully someone can tell me what i did wrong so this doesn't happen again. i am so confused because some of the images came out clear and then on the same settings the next image would be out of focus?
    Please any advise would be appreciated! I have added an example of one image.


     

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  2. 480sparky

    480sparky Chief Free Electron Relocator Supporting Member

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    Looks like the camera moved. There's enough ambient light to create a decent exposure without the speedlight and the camera moved during exposure.
     
  3. jcdeboever

    jcdeboever TPF Supporters Supporting Member

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    I agree with Sparky on the camera movement. If the camera was on a tripod, make sure the VR is off on the lens.

    This is a good example of why you should shoot in manual mode when using the flash. You should set your aperture for desired depth of field and control the ambient light using the shutter speed. Your flash will do the rest. You can set your flash for manual as well and control it's intensity on the flash or in the camera, if your model supports this. You don't tell us what camera model or flash model so I am not sure if you can use HSS. However, you could also shoot in TTL mode (flash and camera) and set your camera's shutter speed at the flash sync speed and set your aperture for the desired depth of field, and then you could compensate the flash intensity using flash compensation in camera if desired. There are other methods and lots of videos on YouTube to get a firm grasp. It is really easy to do, just have to understand the concepts.

    It really helps to have a TTL cable made for your particular brand of camera and get the flash off of the camera. Velo is a good brand of cable and reasonably priced. You would hold the flash in your left hand at a 45° angle from the subject and preferably elbow above the lens, to the left. There are other methods to trigger the flash as well but this is probably the cheapest alternative to bump up the light quality.
     
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  4. vivienne forte

    vivienne forte TPF Noob!

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  5. vivienne forte

    vivienne forte TPF Noob!

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    Thank you for your help, i really appreciate your advice. Ive just looked back on this particular family & i did shoot in manual mode and The flash was always on TTL. . My speed light is SB700 and camera is Nikon 7100. Can you explain how i set my cameras shutter speed to the flash sync speed as im thinking the sync may be off?
     
  6. 480sparky

    480sparky Chief Free Electron Relocator Supporting Member

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    1/100, which is what was used, is the synch speed. The speedlight is producing a shadow, so everything is right with shutter speed and synch. You're just moving the camera too much pushing the button.
     
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  7. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    Blur in a shot which is in focus is typically going to come from one (or both) of two sources - movement of the camera and/or movement of the subject(s).

    In this case the subjects are pretty still and the blur is fairly even over them all; so this suggests that the blur is most likely coming from the camera moving around. If it was motion from the subjects you'd expect natural variation between different subjects and you'd expect the blur to focus on areas of them which were moving - getting stronger in those regions.


    So now we know the likely source is the camera end of the scale we can consider what might be the issue. With a shutter speed of 1/100sec and a focal length of 50mm this is within the typical "good hand holding" region of shutter speeds. The VERY rough rule is that shutter speed is equal to 1/focal length of the lens.

    So with a 50mm you'd expect to be safe up to 1/50sec. So 1/100sec should be more than enough shutter speed.

    Real world experience will vary this; eg going into very wide angle focal lengths 30mm and smaller) one can often find that you can hand hold steady at much slower than normal speeds; conversely once you go beyond around 200mm many often find that they need faster speeds than the 1/focal length guideline suggests.


    That said you're still getting blur. This might then come down to your posture and physical condition/fitness. The rule of thumb noted above is only a guideline and assumes good posture. You might want to consider putting your legs apart a little, ensuring that the camera is held snug toward your face with your hands holding it firm and your elbows down and close to your body. Look up some videos/guides as there's a fair bit about good posture out there.

    If that doesn't yield reliable results then consider using a faster shutter speed. Now as you're using flash this might get a bit more complex. Flash units have a maximum sync speed, which is the fastest shutter speed they can fire at whilst giving a uniform spread of light. This varies camera to camera but its typically around the 1/200 to 1/250sec speeds. Check the manual of the flash/camera for specifics. Any faster and the camera shutter system itself moves its lower shutter curtain before the upper has fully finished opening; so instead of the whole sensor seeing light at once, only a section of it does at any one time. Faster and faster speeds this sliver gets thinner and thinner. If you add flash during those speeds you get thick black bars which is where the shutter curtains are moving and shielding that part of the sensor from the split second of flash light.
    Now many flashes have "high speed sync" mode which uses less power, but fires the light in pulses so that as the shutter curtains move each segment of the exposed sensor gets its own little blast of flash light. Of course this means the flash can't output as much power. It's good for fillflash where you just need the flash to lift the light in the shadows of the shot; but its not good for flash dominated lighting where the flash is providing the majority of the light for the shot.

    Looking at your example shot I'm guessing the flash is more providing fill than main light. If it was providing main light you'd likely not have the blur issue (because the only light contributing meaningfully to the exposure would be the splitsecond of flash light - so you'd not see any blurring that results from a longer exposure of light - which is what the natural light is giving you).


    So in summary - consider reviewing your posture, fitness and shooting stance. Then consider faster shutter speeds up to the sync speed of the camera/flash. If that fails consider using faster shutter speeds in conjunction with highspeed sync mode on the flash (if it supports it).

    As noted above you can also use a tripod which will eliminate handshake as an issue in general. If you want to retain more mobility and speed when shooting you could meet that half way and use a monopod.
     
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  8. wfooshee

    wfooshee No longer a newbie, moving up!

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    I would disregard the pre-flash blinking warning from the previous post. The pre-flash for metering is quick enough that it's not distinguishable by human eye from the main flash. As for blinking when they see it, people will blink at a flash, but the preflash is quick enough that human reflexes won't blink by the main exposure.

    Cats, on the other hand... I can't tell you how many flash picture of cats I have with the eyes closed!

    One thing in the previous post I absolutely agree with: the background is better focused. Even the blue shirt is sharper than other areas of the picture. I really can't tell if that's motion blur or focus blur. The camera may be focusing behind the subjects for some reason. The EXIF data on the image shows 1/100 at f:5.6 with a 50mm lens. If you're too close, your depth of field may be too shallow to include the closer subjects.

    The D7100 will synch flash up to 1/250, so try a faster shutter speed; that's as easy enough thing to do.
     
  9. vivienne forte

    vivienne forte TPF Noob!

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    Okay thank you for your help. I will work on trying to keep my camera very still while shooting. Thanks !
     
  10. vivienne forte

    vivienne forte TPF Noob!

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    This has been really helpful. I have already looked up posture images and will try to be slower when pressing the shutter on my next shoot. Something i hadn't considered before so thank you.
     
  11. vivienne forte

    vivienne forte TPF Noob!

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    I was standing quite far away and using a Nikon 50mm lens which i usually use for close up portraits but the light was really bad that day an it was a choice between my 18-200 or my 50mm which is my favourite lens so i used that one(my first time to use it on a group). Some of the images as you say did show focus on the subject behind rather than where i had actually pressed the focus on. This seems to be a problem with this lens quite a lot. I will focus close on an eye and then when i zoom into the final photo its the ear thats in focus.:-( Would i be better off using the 18-200 for groups of 3 or more people next time?
     
  12. vivienne forte

    vivienne forte TPF Noob!

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    This has been so helpful, thank you. Can i ask you, while i'm using my nikon 50mm lens should my subjects be quite close? is their a maxium distance they should be away before me before the image starts to look out of focus. For example the photo i opload here , are my subjects too far for that particular lens. Should i have used my 18-200mm? Sorry if i sound really dumb but im learning.
     

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