Focusing the Eyes!

sany · 08-05-2011, 09:01 AM

Does focussing in the eye critical even at smaller aperture (higher f number) since the DOF is more can we not simply focus anywhere on the subject that anyway will have the eyes included in focus?

When there is thin DOF eyes could be a target so the even if the corners loose sharpness the subject would look compromising - is this statement right!?

adr1an · 08-05-2011, 09:08 AM

Originally posted by sany

Does focussing in the eye critical even at smaller aperture (higher f number) since the DOF is more can we not simply focus anywhere on the subject that anyway will have the eyes included in focus?

When there is thin DOF eyes could be a target so the even if the corners loose sharpness the subject would look compromising - is this statement right!?

Yes - but I think the logic behind focusing on the eyes means the DoF will be a lot more 'natural' given that at 70mm's (im gussing common Portrait Focal length) 'roughly' 54% in rear, 46% in front. This means that their Eyes, and NOSE, will definately be in focus, and then it will naturally taper out as it moves to the back of the person.

Focusing on say... the back of their Shoulder.. may bring their eyes into focus, and even their nose - but then you'll have a big chunk 'behind' them also in Focus... and remembering that at 70mm, with a focus distance of say 3m's, you've got only a whopping 40cm's of DOF to 'play with'... at F4. Thats 25cm's 'behind' and 15cm's "in front"... not a lot of room for error really..

You dont want to go much higher than F9, because you'll loose sharpness due to Diffraction....

I lift my suggestion from Understanding Depth of Field in Photography

I'm sure however someone with more of a clue will be along shortly to restate the above...

adr1an · 08-06-2011, 09:50 AM

sany; how you going with exploring this ?

Ron Kruger · 08-06-2011, 10:12 AM

Even when using a high f-stop number with a wider DOF, there still remains an exact focal point, though it becomes difficult to determine exactly where that is. What I would suggest is to focus manually, paying attention to the edges of the DOF to include the parts you want in focus and thereby utilizing the maximum of the hyperfocal distance to your advantage. Use flash to fill in AV mode for some dramatic results.

Ratmagiclady · 08-06-2011, 07:04 PM

Originally posted by Ron Kruger

Even when using a high f-stop number with a wider DOF, there still remains an exact focal point, though it becomes difficult to determine exactly where that is. .

That's pretty much the thing, right there: DOF doesn't mean there isn't a precise focal point. it's just harder to see in the viewfinder. Part of the *real* appeal of fast lenses in the manual focus era, rather than any idea you'd shoot them wide-open except as a last resort.

Ron Kruger · 08-07-2011, 10:49 AM

Originally posted by Ratmagiclady

That's pretty much the thing, right there: DOF doesn't mean there isn't a precise focal point. it's just harder to see in the viewfinder. Part of the *real* appeal of fast lenses in the manual focus era, rather than any idea you'd shoot them wide-open except as a last resort.

It just occurred to me that in AV mode, one might set the camera on f-2.8 to determine the exact focal point and lock the focus there, then stop down to the desired f-stop for the desired DOF.

sany · 08-07-2011, 01:22 PM

Originally posted by Ron Kruger

It just occurred to me that in AV mode, one might set the camera on f-2.8 to determine the exact focal point and lock the focus there, then stop down to the desired f-stop for the desired DOF.

+1 , will try this!

08-05-2011, 09:01 AM	#1
sany Veteran Member Join Date: Mar 2011 Location: Dubai, UAE Photos: Gallery \| Albums Posts: 448	Focusing the Eyes! Does focussing in the eye critical even at smaller aperture (higher f number) since the DOF is more can we not simply focus anywhere on the subject that anyway will have the eyes included in focus? When there is thin DOF eyes could be a target so the even if the corners loose sharpness the subject would look compromising - is this statement right!?

08-05-2011, 09:08 AM	#2
adr1an Veteran Member Join Date: Sep 2010 Location: Canberra Photos: Gallery \| Albums Posts: 739	Originally posted by sany Does focussing in the eye critical even at smaller aperture (higher f number) since the DOF is more can we not simply focus anywhere on the subject that anyway will have the eyes included in focus? When there is thin DOF eyes could be a target so the even if the corners loose sharpness the subject would look compromising - is this statement right!? Yes - but I think the logic behind focusing on the eyes means the DoF will be a lot more 'natural' given that at 70mm's (im gussing common Portrait Focal length) 'roughly' 54% in rear, 46% in front. This means that their Eyes, and NOSE, will definately be in focus, and then it will naturally taper out as it moves to the back of the person. Focusing on say... the back of their Shoulder.. may bring their eyes into focus, and even their nose - but then you'll have a big chunk 'behind' them also in Focus... and remembering that at 70mm, with a focus distance of say 3m's, you've got only a whopping 40cm's of DOF to 'play with'... at F4. Thats 25cm's 'behind' and 15cm's "in front"... not a lot of room for error really.. You dont want to go much higher than F9, because you'll loose sharpness due to Diffraction.... I lift my suggestion from Understanding Depth of Field in Photography I'm sure however someone with more of a clue will be along shortly to restate the above... Last edited by adr1an; 08-05-2011 at 10:39 AM.

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08-06-2011, 09:50 AM	#3
adr1an Veteran Member Join Date: Sep 2010 Location: Canberra Photos: Gallery \| Albums Posts: 739	sany; how you going with exploring this ?

08-06-2011, 10:12 AM	#4
Ron Kruger Veteran Member Join Date: Aug 2010 Location: Missouri Posts: 534	Even when using a high f-stop number with a wider DOF, there still remains an exact focal point, though it becomes difficult to determine exactly where that is. What I would suggest is to focus manually, paying attention to the edges of the DOF to include the parts you want in focus and thereby utilizing the maximum of the hyperfocal distance to your advantage. Use flash to fill in AV mode for some dramatic results.

08-06-2011, 07:04 PM	#5
Ratmagiclady Veteran Member Join Date: Nov 2008 Location: GA Photos: Gallery \| Albums Posts: 13,563	Originally posted by Ron Kruger Even when using a high f-stop number with a wider DOF, there still remains an exact focal point, though it becomes difficult to determine exactly where that is. . That's pretty much the thing, right there: DOF doesn't mean there isn't a precise focal point. it's just harder to see in the viewfinder. Part of the real appeal of fast lenses in the manual focus era, rather than any idea you'd shoot them wide-open except as a last resort.

08-07-2011, 10:49 AM	#6
Ron Kruger Veteran Member Join Date: Aug 2010 Location: Missouri Posts: 534	Originally posted by Ratmagiclady That's pretty much the thing, right there: DOF doesn't mean there isn't a precise focal point. it's just harder to see in the viewfinder. Part of the real appeal of fast lenses in the manual focus era, rather than any idea you'd shoot them wide-open except as a last resort. It just occurred to me that in AV mode, one might set the camera on f-2.8 to determine the exact focal point and lock the focus there, then stop down to the desired f-stop for the desired DOF.

08-07-2011, 01:22 PM	#7
sany Veteran Member Join Date: Mar 2011 Location: Dubai, UAE Photos: Gallery \| Albums Posts: 448 Original Poster	Originally posted by Ron Kruger It just occurred to me that in AV mode, one might set the camera on f-2.8 to determine the exact focal point and lock the focus there, then stop down to the desired f-stop for the desired DOF. +1 , will try this!