Hyperfocal distance

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Kwak_Knight

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Ian
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Hi all.
I've got a 550D and I've recently purchased a Sigma 10-20mm 3.5 EX lens.
I'm having difficulty working out what to do to achieve hyperfocal distance with this lens.
Can anybody help me out?
I know my 550D has a crop factor of 1.6
And I believe that my Sigma lens is designed to be used with a cropped sensor
Cheers
Ian
 
Cheers for that :)
I guess the main point I'm stuck on is do I work out the hyperfocal distance as if I were using a full frame camera because the lens is designed for a cropped sensor?
Confusing I know! Haha
 
Kwak_Knight said:
I guess the main point I'm stuck on is do I work out the hyperfocal distance as if I were using a full frame camera
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The short answer to that is no.

Kwak_Knight said:
because the lens is designed for a cropped sensor?
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because the imaging circule of the design doesn't, in itself, make the DoF any different, what you're actually using it on does.*

* usual caveats about for the same field of view, etc. apply
 
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Musicman said:
Once upon a time most lenses had DoF scales on them.
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This is why places like Exeter college teach people on film cameras, so they "learn" basic photography, and it shows that not all supposed "advances" in photography are for the better, bring back DOF scales.
 
You'd think that with all the processing power of the modern DSLR that a built-in DOF display on the camera would be standard.



Just a thought
 
When i had that lens all i ever did for landscape was auto focus on anything at about 8ft away @ f8 then switch to manual. This may not work for you but it was not a problem for me :)
 
Neil B said:
When i had that lens all i ever did for landscape was auto focus on anything at about 8ft away @ f8 then switch to manual. This may not work for you but it was not a problem for me :)
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I'm focusing about 6.6m @f16. It seems to be working ok. Won't know for sure until I can check my pics on my laptop
 
f16? Golly.

One thing to keep in mind is that you don't need DoF to exceed your scene. f8 will probably give you around a couple of feet to infinity at the 10-20mm's wider zoom settings and at the longer end about five feet to infinity so there's hardly a need to go to f-verysmall unless you are doing something like reducing the shutter speed.

Back to the question, deffo use DoF tables for APS-C or something that works just as well is set your focus to infinity and divide the focal length by the aperture to give you the size of smallest thing you want to capture clearly. eg. 50 (mm) divided by 10 (f10) = something 5mm should be captured acceptably sharp, 100 (mm) divided by 8 (f8) = something 12mm should be acceptably sharp. And of course if you use this method you don't have to carry DoF tables about with you.
 
JSER said:
This is why places like Exeter college teach people on film cameras, so they "learn" basic photography, and it shows that not all supposed "advances" in photography are for the better, bring back DOF scales.
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Why do people say this? Almost all prime lenses still have a DoF scale. But they relate to full frame, so not much help with your 60D. There's not room to fit them on a zoom with variable focal length (and yes, I know one or two old push-pull zooms used to have them).

Hyperfocal distance focusing is really easy, and all you need is a handful of numbers to refer to, stuck inside your lens cap. I've posted about it often enough, if anyone wants to search against my user name.
 
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HoppyUK said:
Why do people say this? Almost all prime lenses still have a DoF scale. But they relate to full frame, so not much help with your 60D. There's not room to fit them on a zoom with variable focal length (and yes, I know one or two old push-pull zooms used to have them).

Hyperfocal distance focusing is really easy, and all you need is a handful of numbers to refer to, stuck inside your lens cap. I've posted about it often enough, if anyone wants to search against my user name.
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I said film cameras, ie 35mm with prime lenses.

I have not needed any such assistance for 40+ years as I know what dof I want with a given lens and ap. But even I had to leearn.
 
HoppyUK said:
Why do people say this? Almost all prime lenses still have a DoF scale. But they relate to full frame, so not much help with your 60D. There's not room to fit them on a zoom with variable focal length (and yes, I know one or two old push-pull zooms used to have them).
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Well, that's not all strictly 100% true is it?

I only have three APS-C / FF zooms, all non push / pull, and two of them have distance and DoF markings and a quick look at a well known manufacturers web site reveals several more. I think that the issue is that many newer and budget zooms don't have the markings. Anyway, personally I think that many DoF markings are just too small to be useful but I do find distance scales useful.

It's also worth keeping in mind that hyperfocal tables are probably not going to be as precise as they claim to be in real world use and although it's probably best to use DoF tables for your format, APS-C / FF, in reality I'm not so sure that in real world use it'll really matter all that much but that's a personal choice and 5 minutes checking APS-C / FF DoF tables will show you the difference and then you can make your mind up if it really matters where it counts, in real world use. For example, if you only had one set of tables you could decide that the difference doesn't really matter or you could always work off them and step either up or down a smidgen to cover any error.
 
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