Depth of Field

CH3OH

I have been taking some photos recently and was struggling to get focus in the images. I actually thought it was my lens at one stage.

I have a reasonable understanding of Depth of field, but I would have only been guessing, if someone had asked me what is the depth of field with a 200mm lens shooting at f4.0 focussed on a subject 6 feet away.

Maybe this is very basic, but I came across this site which I think is very useful:

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

I think it is a very handy calculator

dave66

There are a few free iPhone apps for DOF too, couple I have tried:

iDoFCalc
DofCalc Free

They're not bad at all

AnimalRights

I d/l an i-phone app but tbh I've not a clue, I know detailed stuff has been posted here but I just get it in foucs on camera and it works almost all the time.
I do fiind the 50mm 1.4 the hardest to use alright, especially over a distance.
Guess that's something to do with it. :pac:

cnocbui

I'm old fashioned, I just press the DOF preview button on the lens while looking through the viewfinder.

I find I am older than I would like to be - is there an app for that?

AnimalRights

cnocbui wrote: »

I'm old fashioned, I just press the DOF preview button on the lens while looking through the viewfinder.

May this noob ask what advantage is that for?

Kintarō Hattori

AnimalRights wrote: »

May this noob ask what advantage is that for?

Some cameras have a button that when pressed will literally show you the depth of field when looking through the viewfinder.

AnimalRights

Yeah but is that it? I thought it might've been something to do with planes etc
I was out this morning shooting but forgot to test it lol

AnCatDubh

Kintarō Hattori wrote: »

Some cameras have a button that when pressed will literally show you the depth of field when looking through the viewfinder.

Apparently if your camera doesn't have the feature then you can carefully semi release the lens and give it a half turn (so as not to remove it from the body), and it will have the same effect.

The DoF preview takes a little getting used to. I found it's kinda counter intuitive in operation.

DougL

The problem with the DoF preview button is that it closes the aperture down, so at higher apertures, the viewfinder is very dark.

Buckz

Depth of field is bigger (deeper/more margin for error) for small apertures, and further away- so big distance big F number wide view(ie wideangle lens) far maximises depth. Small small narrow (ie telephoto) minimises it.Loosening the lens works on older mechanical ones but not on many current lenses with electrical connections to the camera instead od a mechanical stopdown lever (ah yes, Praktica were the true photographer's machine. )Depth of field previews are good, but DARK, often too dark to be useful. The depth of field scale on a les was great, but you don't see thwm much anymore. So the solution- me no know, but experience helps (experience a nice word for getting it wrong a lot.) for landscapes use a tripod and a smaller aperture and err on the side of safety...

the_monkey

AnimalRights wrote: »

I d/l an i-phone app but tbh I've not a clue, I know detailed stuff has been posted here but I just get it in foucs on camera and it works almost all the time.
I do fiind the 50mm 1.4 the hardest to use alright, especially over a distance.
Guess that's something to do with it. :pac:

it is a pain to use at f1.4 allright, I find it best at around f2/ f2.8 ...

AnimalRights

the_monkey wrote: »

it is a pain to use at f1.4 allright, I find it best at around f2/ f2.8 ...

I find you had to get to 'know the lens' lol
I prefer my 85mm 1.8 when it comes down to a fixed focal lens to use these days anyway but obviously there is the odd time I want to go overboard with crazy bokeh and I use the 50 1.4 wide open.

the_monkey

AnimalRights wrote: »

I find you had to get to 'know the lens' lol
I prefer my 85mm 1.8 when it comes down to a fixed focal lens to use these days anyway but obviously there is the odd time I want to go overboard with crazy bokeh and I use the 50 1.4 wide open.

85 f1.8 - this may be my next purchase, heard a lot of good things about it, even better the 85 f1.2L ... but don't think I could stretch that now


I heard this is the best focal length for portraits on FF ...

5uspect

Regarding the DoF preview. If you flick on Live View it'll gain up the image so it doesn't look as dark as the viewfinder.

I quite like this article on DoF:
http://toothwalker.org/optics/dof.html
He also does a neat little Windows application for calculating it.
http://toothwalker.org/optics/vwdof.html

AnimalRights

the_monkey wrote: »

85 f1.8 - this may be my next purchase, heard a lot of good things about it, even better the 85 f1.2L ... but don't think I could stretch that now


I heard this is the best focal length for portraits on FF ...

One recently went for 250 on adverts.ie, I got mine there last year for 280, generally they go for between 280-300, it's better built then the 50 1.4 too.
Lovely contrasty/rich colours lens.