Portrait Lens for Canon 10D - DOF Issue

Hi there,

 

I have a Canon 10D. I want to purchase a lens for portrait work. I

know abou the 1.6 multiplier. So my choices are the 50mm 1.8 & the

85mm 1.8. They will turn out to be 85mm and 136mm respectively. I

understand that the multiplier just 'crops' the picture. My question

is, will i get a 'portrait look' depth of field from the 50mm lens.

The further away the subject is from the background and the further

away the photographer is from the subject will create more than

enough DOF. Will the DOF make a difference between the 2 lenses.

 

Thank you,

RK

Hi Roger, I don't think the depth of field will change for you on the 10D. With the lenses you mention, you should be able to go from shooting wide open with a nice, blurred background, all the way up to seeing the background quite clearly - around f/11 or so. You'll do just fine. Those lenses are pretty sharp, so you might want to consider a diffusion filter unless you're shooting Angeline Jolie. ;-) Best wishes . . .

See the discussion at http://www.fredmiranda.com/forum/topic/43379

Found a really good article on photo.net about this issue.

http://www.photo.net/learn/optics/dofdigital/

 

Thanks everyone

The 50/1.8 makes an EXCELLENT portrait lens on a 10D since it has the same FOV as an 80mm lens on a full frame SLR. At f1.8 DOF is certainly shallow enough to give excellent background blur. It's also dirt cheap!

 

85mm (136mm FOV equivalent) is a bit longer than is normally used for portrait work.

Since I got my 10D, my 50 1.4 has become my primary portrait lens (I used to use 100 2.0 for portraits). As Bob pointed out it translates to 80mm (not 85) on the 10D which is a tad shorter than I prefer for portraits, but with a 6MP image I can take a couple steps back and crop a bit with no trouble. I shot all formal portraits and group photos at a wedding with this lens and 10D last week and was pleased with the results - groups were not bigger than 8 people.

 

I'd definately go with the 50 1.8 over the 85 1.8 for portraits on the 10D. Everythig I've heard and read about it indicates it is optically as good as the 1.4 - probably the best buy of any Canon lens!

One of the interesting things about digital images (scanned or camera) is that there is a variety of processing options that can be applied to the image. I almost always shoot "portraits" with quite a bit of depth of field and use post-processing to create the look I want. It can be done with a simple diffusion of the background, or, with a gradient, a more DOF-like effect if there is a need for it.<p>

 

Sometimes, I prefer the results to "traditional" DOF effects.<p>

 

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<img src="http://www.spirer.com/images/antigone/cas2.jpg"><br>

<i>The Director, Copyright 2003 Jeff Spirer</i>

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<p>

This one happened to be a scanned image, but the background was sharp (and quite a bit brighter.) The processing would be the same for a digital image.

The print looks very good - this image was done for a one-off book on a theatre production. Printing is very specific to the paper, and in this case, the paper has a creamy tone and very rough (watercolor) surface that benefits from the type of processing done here. However, this still looks better than the vast majority of what is presented on the web from film cameras with "portrait lenses" because of a lack of control by the photographer.

I seldom differ with Bob's opinion, but this is one of those times. FOV cropping does not imply perspective change. A 50mm lens on a 10D will produce the same perspective as on a film camera. Therefore, I prefer 100mm or longer and to increase the working distance. Heck, if I can find the room I try to use my 70-200mm for better bokeh.

The perspective you get from a 50mm lens on a 10D is exactly the same as the perspective you get from a 50mm lens on a 35mm full frame camera. The only difference is that the 10D image is cropped and so the FOV is different. However (and see my comment a few responses down) perspective depends only on shooting distance, not focal length.

 

The question was about DOF, not perspective, but perspective is something to consider.

 

A 50mm can be used for portraits even on a full frame 35mm camera, you just need to be a little careful of it as it can distort features if you get in too close. I've used a 50mm on a 10D for portrait work with some success so it certainly can be effective. However if you want tight headshots you might want something a little longer if you want the classic slightly flattening effect of longer portrait lenses. Your working distance will increase by a factor of 1.6x compared to using the same lens on a 35mm camera though, so make sure you have room enough to back up that far!

Jeff - the probelm with digital blurring of backgrounds is that there is no way to get a distance related blur. Sometimes (as in the case of your example) this doesn't matter, but sometimes it does. Digital background blurring is certainly a tool to use at times, though it's not a substitute for a fast lens.

"The perspective you get from a 50mm lens on a 10D is exactly the same as the perspective you get from a 50mm lens on a 35mm full frame camera."

 

I don't understand what you mean by "perspective". As I understand it, other than DOF, camera systems just scale as far as composition (position and relative magnifications of objects at various distances) is concerned. There aren't any compositional differences between images taken by, say, consumer digital and MF, that I've ever seen, anyway.

 

Thought experiment: If you put the following cameras at the same point (F707 at 20mm, 10D with a 50mm lens, 35mm with an 80mm lens, and a 6x7 with a 150mm lens) and print everything at A4, the shots will be identical in composition. The sizes and positions of every object (regardless of distance from camera) will be identical in every one of the prints.

 

So what does "perspective" mean???

 

(The axe that I'm grinding here is that I think the 10D should be seen as a different format, not as a crop from 35mm. It's about the same amount smaller than 35mm as 35mm is from 645, and nobody talks about 35mm being a crop of 645...)

Bob, you can do DOF in PS with gradient blur. I don't usually have photos that can use this, but I've seen it done it works. You get an effect very similar. There are cases where it won't do it, but it's pretty good. <p>

 

I don't have time to look for examples on the web, but <a href="http://www.digitalcapture.net/Editorial/ReTouch/Vol1/RTV1N1.asp">this page</a> shows how to do it.

Yes, a gradient blur is better but it's still not distance related, and it's distance related blur that can give a true feeling of "depth". Still, PhotoShop does provide a good tool to simulate natural background blur in a lot of cases.

 

BTW I've reconsidered my perspective statement above. A 50mm lens on a 10D DOES give you the same perspective as an 80mm lens on a full frame DSLR. Perspective depends only on distance, NOT on the focal length of the lens. To get the same shot with a 50mm lens on a 10D you have to stand at the same distance as you would with an 80mm lens on a full frame DSLR. Therefore you get identical perspective!

Bob's reconsidered answer is what I have always throught was true.

 

If I put a camera on a tripod and take a picture of an object that is not moving toward me or away from me and use any set of lenses or focal lengths (24,35,50,100,etc)I will get on film (or "on sensor") an image of my subject with the size of the subject varying according to focal length. The subject will be smaller and there will be lots of background with the wide angle lenses whereas the subject will be larger with less background with the longer lenses. If I then enlarge and crop the images taken with the wider lenses so all my images on paper (or computer screen) are now identical in cropping, size of the subject and "print" (paper or screen) size, the "perspective" of the image will be the same. The image of course made with the wide angle lens will be a highly magnified small portion of the original image and will look technically inferior to the same size (subject and print/screen) image made with longer lens.

 

The perspective change that folks appear to be referring to comes into play if the CAMERA is moved closer to the subject so the subject image size on film/sensor is the same regardless of what lens used. Doing this would force one to be very close to a subject with a wide angle lens and farther away with a longer lens and there would be distortion/perspective/etc. changes in the resulting pictures.

 

The "multiplication factor" of a digital SLR is essentially a crop of what the expected image would be with 35mm film. For a 1.5 multiplication factor the image on the dSLR sensor taken with a 50mm lens with produce the same "on sensor" image as a 75mm lens will produce on 35mm film and would have no perspective changes.

 

I use a 50 f1.4 lens on my DSLR and if I take pictue with it and print full frame to a 9 x 6 inch print and then compare it to a picture taken with a 75mm f/1.4 lens with 35mm film camera, also printed full frame to a 9x6 inch print the two prints will be identical from a perspective standpoint. There will be differences perhaps in grain/noise and the qualities of the lenses may differ (color, contrast, "bokeh") but the perspective of the subject to it's background, etc will be the same. The DOF of course with be that of a f/1.4 lens.

 

Robert

Roger if you stand further away with the 85mm lens so that it frames the same as the 50mm would standing closer....They will have IDENTICAL DOF at the same aperture.and as they both have the same maximum apeture,you'll have to decide between them some other way.

If you haven't decided yet from the others recomendations ,i too would go for the 50/1.8 first---but i would really like both!