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Depth of field


steve.elliott

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A quick question. Now I have a Canon f2.8 lens (17-55 IS) this means it's

pretty good for low light. But the problem is depth of field.

 

I haven't used it for indoor people shots yet. So if I have a (narrow)

rectangular table, and 6 people sit each side - will I have enough depth of

field? With low light a compromise is required - otherwise I'd use f8.

 

Has anybody got any examples of low light group shots so I can envisage how it

would look at f2.8?

 

Many thanks, Steve.

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I'm not sure where you got the idea that a F2.8 is lens is fast? Yes it is fast for a zoom, but for a prime lens it is two full stops slow.

 

Next issue is that focal length & distance effect DOF more than aperture. At the distances & focal length you will need to frame 6 people. You will not get very much DOF at F2.8. It is best to stop down and use flash.

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Get a tripod, and go f8. Otherwise I guess if there is enough room for six people then that is a quite big room. If so using one flash only would result uneven lighting.

 

Anyway there are DOF calculators (google for it). At 17mm probably you can get promising DOF even with wider apertures.

 

If the picture printed in large you must produce as sharp image as possible. If it going to be published on the web in a 400x300 jpg then the sharpness is not a big problem.

 

Just my thoughts.

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Why are you hunting groups at all? - If I'm indoors with rather fast glass, I focus on the eyes of somebody interesting and use the rest as blurred background. If your camera has DOF preview keep in mind that you'd have to stop down 2 additional stops to get what you see.
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Hi Stephen, Here's a shot of the band I play with (although only one night a year. To paraphrase Ian Anderson, we're too old to rock & roll, too young to die) taken last night with a 70-200 f/2.8L IS at f/2.8, ISO 1600, 1Ds Mark II.

 

I don't think it qualifies as a "group" shot in the same way you meant it though! ;-) Also everyone's sort of in the same focal plane in the shot. No tripod, no flash.

 

In general, wide-angle lenses should give you more DOF than long zooms though.

 

You could easily hit your f/8 goal by using a flash I would think, but sometimes you just can't use them for various reasons.

 

If anyone ever suggests taking up the drums, I say get a harmonica instead. Much easier to carry around and I doubt I'd be injecting Ibuprofen in my jugular vein this morning.<div>00Ivgw-33696084.jpg.7f1fce38eb0619f523021a26642fdda3.jpg</div>

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"Is it possible to take the shot before they sit at the table"

 

That may be the way to go. Or put everyone on 1 side like "The Last Supper" ;-)

 

Just another thought but if you could instruct people to remain reasonably still while seated (you'll probably have a long shutter speed) you could then shoot in Av mode on a tripod while bouncing the flash which may give you decent ambient light without a harsh shadow. I know - easier said than done but if you have a low-noise camera like a 5D you can really crank the ISO thus helping the shutter speed issue. Another probably crazy thought - perhaps using hotlights which (usually) have a very similar color temperature to good old lightbulbs, if that's what's used to illuminate the room.

 

I'm pretty sure that at f/2.8 the people at the far end of the table will be rather fuzzy without bringing in some extra light so you can stop your lens down a bit.

 

One last, totally insane thought - due to staying up all night - mount the camera, centered directly above the table, facing down with everyone looking up. Seems you'd need much less DOF. Yeah I know... ;-)

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If this is just a one-shot deal for your team just pose them in a group away from the table.

 

Shooting down the table will be almost impossible, even with f8. F22 might do the job but then they will be blurred from movement.

 

You could try aiming a flash straight down the middle, possibly at a telephoto or medium zoom, and seeing if the penumbra will take care of the closest people.

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Er.. with my fisheye the DOF starts from five feets and ends at the infinity even at the widest aperture. So it is possible, but most probably useless to have a fisheye pics of them.

 

<A href="http://foto.c3d.hu/cgi-bin/yaweg?ShIMG:fisherteahaza:img_5665.jpg"> here is a full fisheye</A>, and a <a href="http://foto.c3d.hu/cgi-bin/yaweg?ShIMG:fisherteahaza:leonofsgr.jpg">cut version</a>, and I have played with <a href="http://pano.teahaz.net/01.html">panorama</a> tools too.

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