Circles of Confusion

[Barney]

It's almost getting to be a permanent state of affairs for me.

What effect does the film have on the CoC if any, is it purely an enlargement phenomenon? or a combination of several factors?

 

[StephenM]

None at all. It's optical. And it's a defined quantity at that. Purely arbitrary. Part objective, part subjective. But it depends only on the personal opinion and assumptions of the person who set it.

Edit to add. The film is not part of any consideration of the value to assume. Your eyesight is - and no one setting the value knows or cares how good your eyesight is. They assume you're standard.

 

[LeeRatters]

Just go and take photos .....

 

[Barney]

Just go and take photos .....

Took Loads already today and developed a colour film and a B&W film.

 

[woof woof]

I don't think this is ever going to be a real world issue if you live to be a hundred and twenty twelve and are still shooting.

CoC reminds me of my computer days, there's some stuff you really don't need to know and even if you know it it'll only ever cross your mind when you know you really should just stop.

 

[AndrewFlannigan]

What effect does the film have on the CoC if any, is it purely an enlargement phenomenon? or a combination of several factors?

Wellll, I suppose a straight answer is that when you expose the film, the circle of confusion of the taking lens has an effect on the sharpness of the image recorded on the film.

If and when you make a print from the exposed and developed film, the circle of confusion of the enlarging lens has a further effect on the sharpness of the print.

However, back in the real world, all that really matters is whether the person viewing the image is even interested in the sharpness of the image or is just thinking "what a sweet baby"...

 

[myotis]

It's almost getting to be a permanent state of affairs for me.

What effect does the film have on the CoC if any, is it purely an enlargement phenomenon? or a combination of several factors?

Can I suggest Cambridge in Colour as a resource to look things up. Simple questions often require long and complex answers, and in general, I've found the pages here to have a reasonable balance between technical exactness and readability.

This page is about depth of field and discusses C0fC as it's fundamental to understanding depth of field.

Understanding Depth of Field in Photography

www.cambridgeincolour.com

 

[sk66]

is it purely an enlargement phenomenon?

Yes. It's simply a matter of whether a point of light (airy disk/detail) is focused small enough to be considered acceptably sharp when viewed in the displayed (enlarged) image.

But the CoC standard makes several assumptions so that it is almost arbitrary.