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Close-up filters - Effect on depth of field

PostPosted: Wed Oct 05, 2005 2:35 pm
by leek
Does anyone know how to calculate the depth of field for a given lens and a given aperture when +1, +2 or +4 closeup filters are fitted???

PostPosted: Wed Oct 05, 2005 3:44 pm
by ozonejunkie
I have never experimented much with it, but a while ago I stumbled upon this:

http://ca.geocities.com/lokejul/jlcalc.htm

Hopefully you can make some sense out of it.

Tristan

PostPosted: Wed Oct 05, 2005 4:23 pm
by moggy
What an awesome program Tristan, thanks for the link. :wink:


8) Bob.

PostPosted: Wed Oct 05, 2005 5:21 pm
by leek
Thanks Tristan - Just what I needed... It confirmed my suspicion that I was playing with 0.5mm Depth of Field earlier today - no wonder it was so damned difficult to focus :lol:

PostPosted: Wed Oct 05, 2005 6:16 pm
by ozonejunkie
leek wrote:Thanks Tristan - Just what I needed... It confirmed my suspicion that I was playing with 0.5mm Depth of Field earlier today - no wonder it was so damned difficult to focus :lol:


Yes, that was the reason that I tried to find this exact program. I bought a +3 close up filter about 3 weeks ago, and whilst playing with it, discovered that focus is really, really touchy. Then I realised how small my DOF was. :|

It took a while to get used to, but I love it these days!

Tristan

PostPosted: Wed Oct 05, 2005 11:36 pm
by Onyx
f/22 is your friend. ;)

(and so is a tripod if you're at f/22 shooting macros)

PostPosted: Thu Oct 06, 2005 2:53 am
by xorl
Flash can also make it possible to use tiny apertures for macro work. You may not need the tripod then..

PostPosted: Thu Oct 06, 2005 8:22 am
by Aussie Dave
just curious as to people's thoughts on playing with such a very shallow DOF, with the close-up filters ? Shooting with a DOF of 0.5mm, in my mind, would not be conducive to pleasing photos....leaving foreground/background OOF.

All too often we see people posting amazing macro photos and the comments/critiques that seem to be prevalent in all these is, "nice shot, but it would have been better if the [xxx] was in focus, as well".

Unless you are taking photos of salt grains, I don't see how you could ever expect to have a deep enough DOF to obtain fully pleasing macro photos - using these c-up filters.

I have thought about getting some c-up's but I keep coming back to this same question.

Am I missing something ?

PostPosted: Thu Oct 06, 2005 8:39 am
by leek
Aussie Dave wrote:Unless you are taking photos of salt grains, I don't see how you could ever expect to have a deep enough DOF to obtain fully pleasing macro photos - using these c-up filters.


Thaddeus and I found this image to be quite pleasing... :lol:
Image

The out of focus areas can introduce nice dreamy effects similar not too dissimilar to the bokeh effect that many strive to achieve in their normal photos...

You only get down to .5mm DOF with extremely long lenses and high magnification... Usually you have the luxury of several mms :lol:

I find that the 52mm Closeup filters work really well on the 50mm and 105mm primes... As you may have seen - I just bought a set for the 80-400VR as well - this was more for the pleasure of experimentation...