100mm 2.8 macro usm shallow dof

[jonah_levine1]

I just purchased the 100mm 2.8macro usm over the ef 85mm f1.8.

While the lens is a little slower, having macro capabilities was definitely

attractive to me since I can't buy thousands of lenses.

 

I'm going to be using this lens 90% for portraits. I am trying to achieve a

shallow dof, where eyes are in focus while nose and ears are blurred. I have

had good success in doing this with a 4by5

 

In order to do so with the 100/2.8macro, I need to move so close to the subject

that I have to crop in on the head of the model. If I step away to frame the

entire head the effect isn't noticeable enough. Has anybody been succesfull

in achieving this with any of the canon primes portrait lenses (besides L

series....too expensive...)

[michiel_bernhard]

Hi Jonah,

 

With f/2.8 and a distance of 2 meters DOF with the 100 mm will range from 1.97 meter to 2.03 meters.

 

Hope this helpes, I can provide you with an Excel add-in to calculate DOF.

 

Michiel, Holland

[peter_foiles2]

Jonah:

You have run up against the laws of optics, in short you can't do what you want with the

lens that you have. An unavoidable consequence of moving to a smaller format is that you

gain depth of field whether you want it or not. To start at the beginning. DOF is dictated

by the focal length of the lens and the aperture, nothing else. This is not something that

varies by brand or cost or anything else. For shallow DOF you want long focal length and

wide aperture. Now for your 4x5 a "normal" lens would be about a 160mm or so, and you

may well have been using a lens in the 200-300mm range for portraits. A normal lens for

35mm film is about 50mm and for dSLRs like the dRebel or 10D it is about 28mm. Much

shorter focal lengths = much more DOF, unavoidable. If shallow DOF is what you want the

85/1.8 may have actually been the better choice. You may also want to consider a 50/1.4.

[bobatkins]

<em>Much shorter focal lengths = much more DOF</em>

<p>

While this is true for shots in which you're getting close to the hyperfocal distance of the lens, it's not true for semi-macro type work (which this is). DOF in that case will be a function mainly of magnification and aperture, so to get less DOF you have to move to a wider aperture lens.

</em>

The 85/1.8 would have been a slightly better choice for this application, but as pointed out above, increased DOF is a consequence of a smaller format.

<p>

The cheapest solution might be to pick up something like an older Pentax 50/1.4 screwmount lens and use a Pentax Screw to EOS adapter. However on a full frame body, 50mm is a bit short for closeup portraits.

<p>

Another route would be to use a 90mm/2.8 T/S lens and use the tilt function to isolate focus on the eyes. However that's also a $1200 solution.

[digitmstr]

You didn't say what format/camera you are using (digital/film/crop). However, since longer lenses begin to "flatten" (compress) DOF effect changes as well.

 

If you are using a film camera a 50mm or 85 will work better. Even for digital with a 1.6 crop factor. B&H used to have quite a few used FD 50 f/1.4 in great shape. You could get one of those "lensless" FD>EOS adapters and you will have great lens for isolating focus in portraits.

 

But, even a 50 1.8 can do that...

[jonah_levine1]

Oh by the way...I posted the same question on the portrait photography forum and got slammed. I guess a lot of people think this lens is too sharp for portraiture..showing every wrinkle.

 

Regarding the shallow dof...it's a neat trick and I will keep doing it with larger formats...but I'll put it aside for 35mm.

 

DOF tricks aside, I think 85mm might not be quite long enough?...100mm-135mm...is what feels right to me distortion wise.

Where does that leave me, I can still return the lens... :)

[peter_foiles2]

The only other options are the 100/2 at about $375 or the surplative 135/2L at about $860. I would recommend the 135 even if it breaks your budget, it is a true world class optic and a bargan at $860.

[gaius1]

<a href="http://tangentsoft.net/fcalc/">f/Calc</a> is your friend. I usually do a few calculations with it before setting out on a shoot, commit to memory the aperture/distance/DOF numbers that I expect to use. Of course I've forgotten them the next day but that doesn't matter, tomorrow's another roll of film :-)

[gaius1]

Oh, and Canon also has a 135mm f/2.8 SF lens, which is highly regarded for portraiture. It's pre-USM tho', tho' for formal poses I guess that wouldn't be a problem. Much cheaper than the 135mm f/2L.

[michael_peters1]

<i>Oh by the way...I posted the same question on the portrait photography forum and got slammed. I guess a lot of people think this lens is too sharp for portraiture..showing every wrinkle.</i>

<br> <br>

Snobs. My old photography teacher taught me this trick - take a piece of white pantyhose and stretch it over the lens with a rubber band. That'll soften up the focus. Or buy a SF filter set.

<br> <br>

The 85/2L is also incredibly sharp - and quite often used for portraits. When the image needs to be softened, it is softened by a filter or post process. The snobs that diss the macro lens as too sharp seem to forget that - I guess because it's L glass that's OK for their snobbiness.

<br> <br>

Soft focus is really only needed for glamour portraiture - which to be honest, I'm a little sick of. Soft focus has been WAY overdone. IMHO. I'm not a portrait photographer, so add salt to what I say.

[cathyscholl]

Funny, I have this lens with just the opposite problem.

I am also using it for portraits and WANT to crop off heads and want to work as close as possible to the subject but I don't like the fact that there's no DOF when doing so. I love the sharpness of what's in focus however.

 

I'll probably wind up selling it.

 

Cathy