Focal Lengths!!!

[rishabh_destiny]

I'm new to the SLR world and prior to that, I've been shooting quite a lot with my point and shoot. But in this SLR world, there seems to be a lot of confusion for me regarding focal lengths. Not that I'm a n00b at these, I totally understand the wide-angles, telephotos, shutterspeeds, aperture values, ISO etc...

But just reading about focal lengths, I can't seem to get the real feeling. So, I'm asking real photographers out there...

I'm more into portrait photography where it is highly required to isolate the subject from the backgorund, blurring the background.

Now my question is, which focal length offers the most washed out and blurred (with bokeh) background working on a portrait? Please consider both waist up and full body portraits.

Thanks!

[RichardTaylor]

Anything that will produce a shallow DOF of around 200mm (or around 8") or preferably less at the aperture you want to use should be ok.
It depends on your shooting distance and how far away the background is.

This DOF calculator may help.

Online Depth of Field Calculator

The bokeh quality will depend on the lens construction and the background. The more aperture blades the better.

I think any lens >= 50mm and at least F2/F2.8 (to 135mm) and F4 @ 200mm should be fine. At more than 200mm even F5.6 should be OK.

Most of my portraits tend to be candid "head shots" and usually shot with a 135 F2 or 70-200mm lens.

Here are some examples, with "messy" backgrounds. If you can keep you backgrounds "clean" it will help a lot.

(1) 135mm @ F2 on a 40D


(2) 188mm @ F4 on a 40D


(3) 135mm @ F2 on a 40D


(4) However if you are close to your subject even 35mm @ F2 can be OK (on a 5D)

[rishabh_destiny]

Thank you so much for such a great explanation mate I think 135mm will be the best bet considering that I won't be *that* close to the subjects and since 70-200 is quite an expensive lens as for now.

Thank you one again

[RichardTaylor]

Those 135 F2 pics were taken with a Canon 135mm F2 L which is dearer than the 70-200 F4 L.

If you are on a smaller budget you may want to consider the Canon 85 F1.8 or the Canon 100 F2 which are approx 1/2 the price of the 135 F2 L.

[rishabh_destiny]

Thanks for the recommendation Richard. And let me tell you, I have an EOS 550D is having a crop factor of 1.6 I guess. Considering this, what will be your final verdict as per the lens to chose from? I *may* collect enough funds to go for the 135/f2 L which no doubt looks fabulous on your cam, but will it give the same results with my camera body?

Other lenses I'm keeping in mind are Canon 85 F1.8 or the Canon 100 F2 (as you suggested).
The funny part is, I think I'll be completely dropping the idea of a 50mm.. lol :P

[BigVinnie]

I think the 100 f/2 is the most overlooked gems in the Canon line. I tried out both it and the 85 1.8 and went with the 100. I have an XSi which is the same crop factor as yours.

They are built almost identical but the angle of view on the 100 is just a bit better for what I wanted. Mostly because when I was using my zoom I was pretty much always out to the max of 105.

I just got mine yesterday. If I can escape the house this evening I intend to go give it a workout.

[RichardTaylor]

I would still keep the 50mm F1.8 in mind for those occasions when you don't have a lot of working room.

The 135mm F2 works well on any body..

[sk66]

A wider aperture will give shallower DOF for a given focal distance as will a longer focal length...So the longest lens with the widest aperture will have the shallowest DOF for blurring the background...Focal distance matters as much OR MORE than aperture...

I would not choose an excessively long lens...for portraiture you want intimacy, and working close with wider lenses helps.

[inkista]

Originally Posted by RichardTaylor

The 135mm F2 works well on any body..

+1


Canon XT/350D. EF 135mm f/2L USM. iso 800, f/2, 1/1600s.

But you do tend to run backwards with it on the camera, if you don't want a headshot.