You are absolutely right – the crop factor of full frame is taken into account in the coc. ie DSLR crop factor of 1.6 the coc is 0.02 and a DSLR full frame the coc is 0.03.

Thanks for you reply to R.

Martin

MK ’s reply below is right. The CoC is taken into account with the different types of camera you can use so you don’t need to use the 1.6 in your calculation. Use coc of 0.02 for a DSLR with a crop factor of 1.6. Use coc of 0.03 for a Full Frame DSLR (ie canon eos 5d mk 11).

Hope this helps.

Martin

Thanks for this and sorry for the delay in replying as I have been extremely busy with doing photography courses. Using a focal length of 24 on either of these lenses should produce the same result providing you are using the same aperture ie f13 and the same camera. If your camera is either a film camera or DSLR full frame then the circle of confusion should be 0.03 if it’s a DSLR crop factor of 1.6 then the CoC should be 0.02. Therefore DSLR full frame / film at a focal length of 24 at f13 the hfd should be around 1.75 meters. A DSLR crop factor of 1.6 should be around 2.6 meters. Just make sure that you change the focusing point on your camera to focus on this distance which sometimes isn’t easy. As you have mentioned focusing at infinity will make sure that this area is in focus but only half way between infinity and where you are stood will also be in focus. This is why your foreground is now out of focus. Hope this helps.
Martin.

However, I found your info interesting. One will never find me ‘down the camera club’ talking about this stuff as I would rather just go out and shoot!

Thanks for your post and I wish you well.

braydon

Again – thanks for the clear explanation. Best I’ve seen!

Clear description of Hyperfocal distance, thankyou

I do however have a question, I have recently bought a canon 24-70 F.2.8 lens and rather than extending fully at 70mm (like the 105mm on the 24-105 lens), it extends the opposite way i.e. fully at 24mm, does this make a difference to the Hyperfocal distance calculation.

I tried the calculation which I’m already familiar with and have used on previous lens’s with fine results, the result for this lens was as follows

Forground roughly 80cm
therefore using an aperture of F/13 and setting the hyperfocal distance of about 1.5m meant I should have had an image that was sharpe from 75cm to infinity, however anything past about 20feet becomes unexceptable with the far distance being very un-sharpe. Re taking an Image at infinity made the background much sharper (obviously this made the foregound un-sharp). Do you have any suggestions? Could it be an effect of the lens as mentioned above?

Kind Regards

Eli

I have a Canon 500D – crop factor 1.6
Circle of Confusion, according to your guidelines: 0.02
I will still to take some shots at different apertures above f11 but for now, i’ll consider f11 as the best

The problem is that I don’t end-up with the same values you do. For instance, at 17mm aperture, calculation would go as (I think):

17 x 1.6 = 27.2

HD = [(27.2)^2 ] / (0.02 * 11) = 739.84 / 0.22 = aprox 3363 (3.36 m)

IN YOUR TABLE THE VALUE IS 1.43m

why?