EOS R8 & EF 24-70mm lens: Blurry body parts on a full figure picture

[longqin11368]

 

 Hi there, I’m relatively new to photography. Both photos were taken using Canon R8 mirrorless camera plus 24-70mm ef lens @ 38mm, f2.8 1/60,iso400. It was right after sunset. The question is why the lower part of the photo especially the foot and the foreground stones in the second photo blurry? I actually took a series of photos that day and most of them came out with blurry feet.

Your response is greatly appreciated!

[shadowsports]

Greetings,

F2.8 will produce a shallow depth of field.  That coupled with a slower shutter speed can produce motion blur if you aren't holding completely still.  

Were you focusing manually or using AF?  What were you focusing on?  Or what was the camera focusing on?

[longqin11368]

Thank you for your reply! To answer your questions, I was using AF, focusing on the center of her face. You mentioned motion blur, is it possible to have motion blur on just part of a photo?

[AtticusLake]

Just note that AF doesn't make any difference to motion blur or depth of field - motion blur happens after the shutter is pressed, regardless of how you focussed, and depth of field come from your aperture.

But yes, you can get motion blur on just part of a photo, if that part of the subject moves, OR if the camera moves.

You're shooting at 1/60, which is pretty much on the edge for hand-holding.  And I guess your model wasn't perfectly still.  If the breeze moved her dress, for example, even just subtly, that could cause motion blur.

Or if you move the camera. Say you're aimed at the centre of her face, and just rotate the camera very slightly.  The centre of rotation - the face - will show virtually no motion, while parts of the image farther away will show progressively more motion.

You could try a faster shutter, and a wider aperture, by bumping up the ISO - ISO400 is pretty conservative, so you might find a few stops of ISO doesn't hurt much.  Even if you get a little noise, it can be reduced f=very well in post.  Also putting the camera on sticks will help.  Even if you use a video head and pan and tilt around, it will be a lot more stable during each shot.

Nice pics BTW!  The light on her face in the first one is great.

[p4pictures]

For a full-length shot like this at 38mm then I would assume you are around 12 feet from the person. At such distance the depth of field is just over 5 feet, so that means movement of the subject is the cause. 

In my experience people move / breathe while they are being photographed, and this means you need to use a suitable shutter speed to freeze that movement. Photographers also move while holding the camera. I would suggest a minimum of 1/125 and possibly more if the person is moving more quickly. Yes this means you will have to raise the ISO beyond ISO 400, but your EOS R8 is more than capable at higher ISO settings, even ISO 1600 will allow you to shoot at 1/250 f/2.8 and it's hard to tell the difference between ISO 400 and ISO 1600 on the EOS R8.