focus problems.

ziggy53

pathfinder wrote: »

... They used to make a hand held flat disc like a filght calculator I think, but I haven't sen one for years. Maybe Ziggy knows of one.

...

For those thinking DIY:

http://www.dofmaster.com/custom.html

amadeus

thanks again for all the input. I'd never thought of it being onboard the camera.

that would be incredibly simple.

here's a study in DOF shot on burst mode. these are sequential no deletions.

note pic one green bike in focus.

pic 2 red bike in focus.


why would DOF change?

holy cow I just looked and focal length changed - I was zooming while the bikes were passing.


but the aperture didn't change???? I thought DOF was not effected by focal length?

christ I must have been backpedaling. I do that...

some of the calculations I was doing on the posted link had a DOF of like 1-2 feet with what I thought was usual distances I'm working with.





I always shoot manual. how does aperture priority know what your DOF needs will be? it can't?

mstens

Well, here's why I didn't believe it until I tried it. What's important in all of the discussion above is that the size of the subject HAS to be identical. When you change focal lengths you tend to end up, compositionally speaking, with an image where the subject's size in the image is different.

When you select your aperture, that will effectively select your DoF. All that will happen from this point is that your camera will select shutter speed, this can be bad shooting sports (depending on what you're looking for).

While I'm at it the second image is a very strong image in my opinion. You've got great focus on the foreground subject, with a nice DoF and in addition some panning and motion blur. Very nice, I like it.

puzzledpaul

Re post 33 - isn't it possible the AF point is now on some part of the foreground rider?

Nice shot btw

pp

TonyCooper

What I want to know is how much you had to pay them
to get in place and take in all those vintage bikes!

I know I'd pay an admission price.