Canon 300mm f/2.8 IS L

  • Thread starter Thread starter smr
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I think you 'unpack' your question.....as in

When on a tripod/stable surface does it focus reliably?

When handheld what are you photographing and what shutter speed(s) plus whether S-AF or C-AF???
 
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What are you taking photos of that you aren't getting sharp, and what shutter speeds are you using?

I hand hold mine all the time and don't have any issues getting sharp photos. I think I've only used it on a monopod once, but struggled with panning shots so reverted to hand holding.
 
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smr said:
It might actually be more to do with the depth of field I seem to use a lot with it, but I'm sure I was focusing on his eyes, AI Servo mode, 1/1250, ISO 1250, f/2.8

I was using mainly f/2.8 as I was shooting through the fence at YWP a couple of weeks ago.


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At f2.8 the DoF will be razor thin as you are close!

In regard to the 'focus point' AFAIK Canon's DPP software will show which FP was used and hence what part of the face. I think with a plugin Lightroom also shows the Canon FP's
 
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As mentioned above, it's to do with the very narrow depth of field which is likely to be a few cm at best using f2.8 at close range. If using AI servo mode for this type of shot, make sure you are using a single focus point on the eye, as if you have all points selected, the camera will generally choose the closest point distance wise (i.e. nose) which looks very sharp to me in the above photo.
 
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Hi agree it’s depth of field at that close a distance
I shoot big cats a lot in zoos etc with that lens and would use F6.3 as a starting point for that subject at that distance on full frame
A bit further away you can go to F4
 
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smr said:
It might actually be more to do with the depth of field I seem to use a lot with it, but I'm sure I was focusing on his eyes, AI Servo mode, 1/1250, ISO 1250, f/2.8

I was using mainly f/2.8 as I was shooting through the fence at YWP a couple of weeks ago.


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If the focus point was on the eye then the lens is front focusing. The nose is pin sharp. As others have said the DoF at close distance and f/2.8 will be razor thin so any front / back focus issues will be glaringly obvious
 
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smr said:
Thanks for the DPP mention, hadn't heard of this software before. It looks very good!

So I've just installed it - does this mean my Lens is front focusing?

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Hard to say to be honest it could well have focused on the side of the nose
You could do some test shots of static object to check
 
smr said:
Thanks for the DPP mention, hadn't heard of this software before. It looks very good!

So I've just installed it - does this mean my Lens is front focusing?

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In the main I used to find Canon Servo-AF very good but and AFAIK it can 'hunt' a little so that combined with the fact that you have the AF set to multi point rather in such situations as this, where a Single AF point is way more IMO preferable.

The only way to test for front or back focusing is to do as @LCPete says and do a proper test using a static target (a row of batteries is a good rough and ready subject matter) and more importantly a single AF point.
 
smr said:
Ok thanks, I think as you say it's the Depth of Field at f/2.8 and it being extremely narrow especially when the subject is close up. He must have only been 10 feet away.

I'll have to try shooting at other apertures.

I suppose if I had the R6 with eye tracking shooting at 2.8 would be fine?
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To be honest I would still use a smaller aperture it’s not the focus point just small dep th of field when you are close up
With eye focus on my R5 if I use too wide an aperture the eyes will be sharp but nose won’t be in focus
 
With that zone focus the camera did its best and hit the bit at the front i.e. the nose. Try spot or single point focus for the eyes (not easy on moving targets). Nothing wrong with the lens (y)
 
I had a go with this DOF calculator

Online Depth of Field Calculator

Depth of field and hyperfocal distance calculator
www.dofmaster.com

As an example, with a 7D, 300mm, f/2.8, 10ft away: Depth of of field is only 0.03 ft, which is just under 1/2”.

So, at f/2.8 and close up, it very much comes down to choosing what you want/need to be sharp and choose the appropriate focus point, because pretty much everything else won’t be in focus.
 
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