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Old Jul 30, 2007, 10:09 AM   #1
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I am interested in taking portrait shots with a shallow depth of field (blurred background). Does the Canon S5 have adequate aperture settings to accomplish this? If not, I would consider the Canon XT or XTi if the kit lens would be sufficient, but I don't want to have to spend a fortune upgrading the lens. How does the S5 compare to the kit lens on the XT or XTi? Any feedback would be appreciated.
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Old Jul 30, 2007, 11:51 AM   #2
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Depth of field is a function of the focal length of the lens as well as the aperture. The shorter the lens the deeper the depth of field.

The Canon S5 lens covers 6mm to 72mm. At 6mm the depth of field will be from the front element to infinity at just about any aperture setting! At 72mm you will start to see a difference between wide open and fully stopped down but at the cost of being quite far away from the subject. You may not get the effect you're looking for however.

Portrait lenses usually start around 105mm to about 135mm and usually f/1.4 to really get that shallow depth of field to drop out the background


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Old Jul 30, 2007, 4:54 PM   #3
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Thanks for your reply Bob. About how much does theportrait lens that you refer to sell for? The Canon XT and XTi SLR's that I've looked at come with a 18-55mm lens -- will this help me at all or will I really need to upgrade to a nicer portrait lens?
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Old Jul 30, 2007, 9:10 PM   #4
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I don't know what part of the world you live in nor am I that familiar with the Canon line so I can't really advise you.

Here is the Canon Canada lens catalog http://www.canon.ca/english/index-pr...d=2&sgid=7 and here is a good review site http://www.slrgear.com/reviews/index.php

The Canon EF 100mm f/2 USM and Canon EF 135mm f/2L USM (Tested) have good reviews there. Price them out at your local dealer.

The 18-55mm is a bit on the slow side so won't get that really shallow dept of field you want.
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Old Jul 30, 2007, 10:30 PM   #5
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The Canon XT and XTi SLR's are both APSc sized sensor cameras so multiply any lens focal length by 1.6 to get is apparent field of view. However the Depth of Field is still tied to the real focal length.

If you don't mind primes theCanon ef 85 f/1.8 is very nice and not too expensive.

There is a great on-line DOF calculator that will let you see what will be in or out of focus for afocal length/ f-stop combination at http://dofmaster.com/dofjs.html



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Old Jul 31, 2007, 2:44 AM   #6
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Explaining DOF in English (or any natural language) is very difficult.

The best way to understand it is to read the equations and play with some values to get a feel for how it all works.

It is a function of many things, aperture, focal length, sensor size, and one that most people forget - distance from the subject!

And one of the things you're interested in isn't actually about DOF at all really - it's separation of the subject from its background.

Very shallow DOF brings as many problems in portraits as it solves, and most professional portrait work is done with a relatively small aperture - f8 or so but using a controlled background that looks like it is out of focus even when it isn't.

Not all portrait work is best done with telephoto lenses, in fact I prefer a normal or even moderately wide angle lens for my portraits.

Lighting is crucial of course, and that means learning at least something about flash and under which conditions its use is necessary.

I don't mean to put you off, but moving from snapshot portraits to a professional or artistic level isn't achieved simply by purchasing an entry-level DSLR. It's a big complicated subject and with portraiture perhaps more than anything else the equipment is not the biggest part of the equation.

When shooting sports or wildlife expensive equipment is almost essential for decent results. With portraits however expensive equipment simply gives you more creative options, it's neither a necessary nor sufficient condition for excellence.
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Old Aug 2, 2007, 1:56 AM   #7
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However when it comes to P&S's deep DOF is almost impossible (but for extremely close) due to the much smaller sensor size vs DSLR.... which has much the same effect as smaller F/stop. At equal exposere (F & Shutter) a SLR will have much deeper DOF than a P&S.... and also the quality called Boketh... the quality of the background blur more or less.
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Old Aug 2, 2007, 2:47 AM   #8
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Most people use "deep" DOF to mean that the DOF is extensive from the near to the far distance, and "shallow" DOF to mean that the DOF does not extend far from the plane of focus.

According to this common understanding Hayward has his statement above turned around 180 degrees. P&S cameras generally have trouble providing shallow DOF, deep DOF is what they do by default.

The biggest factor in the equation is not the small sensor size (though this matters in determining COC) but it is rather the focal length of the lens used to give the standard fields of view that most people want.

So as Bob says above the 6mm real focal length of the S5 lens at its wide end (which provides an equivalent field of view to a 35mm lens on "full-frame") is a bigger factor in the equation than the sizeof the sensor.

Difficult to explain in English - the equations make it clear though.

"Bokeh" is determined chiefly by the design of the lens and is not in general related to sensor size or focal length. More expensive lenses tend to have more effort put into making attractive bokeh.
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Old Aug 9, 2007, 6:18 PM   #9
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peripatetic wrote:
Quote:
According to this common understanding Hayward has his statement above turned around 180 degrees. P&S cameras generally have trouble providing shallow DOF, deep DOF is what they do by default.

The biggest factor in the equation is not the small sensor size (though this matters in determining COC) but it is rather the focal length of the lens used to give the standard fields of view that most people want.


"Bokeh" is determined chiefly by the design of the lens and is not in general related to sensor size or focal length. More expensive lenses tend to have more effort put into making attractive bokeh.
gawd,
i see he's the same here as he is in the pentax dslr forum. mis/dis information.. it's quite his bench/hall mark.

roy
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Old May 26, 2008, 5:28 PM   #10
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Same problem here with my S5...



Is there any cheat availlable like using some converter lens ?



I sometime use the macro mode for some portrait to get a shallow DOF, only problem is I have to be very close to my subject. Would it help to use a close-up/macro lens to enable me to shoot from a bit farther away and still get a similar result ?
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