DOF for portraits on different formats

[Paul L]

Well trodden on the internet but would appreciate the thoughts of those with knowledge on 4/3, DX, FF etc.

4/3 portraiture not ideal I presume due to deeper DOF for equivalent settings. With my Oly E510 it means a 50mm F2.0 is the only realistic option assuming I stick to F2.0 to F4.0

Although there is some info out there it's a but sketchy so trying to decide whether to go down this route (I want AF not legacy 3mm MF lenses) or abandon and go towards Penikanon for respective lens strengths. It's the lenses that will dictate choice more than the bodies although it still looks like a pivotal time between DX and FF.

It's a confusing market out there. What am I trying to achieve? Just get bakc to the digital equivalent of my old short telephoto 35mm shooting of family portraiture and I get the impression I need faster glass for DOF rather than speed per se. That and shoot more and do the E510 justice.

 

[Mr_Sukebe]

As I understand it, the DOF is directly related to the sensor size/crop. The 4/3rds cameras at the moment have a 2:1 crop. The result is a DOF that's double that of an FF camera, or roughly 1/3rd deeper than a typical crop DSLR.

I did a little looking at 4/3rds cameras, and couldn't help but notice that there was a 20mm F1.7 pancake lens available (can't remember the brand). That would be the equivalent of a 40mm lens on a 35mm film camera. Whilst the DOF won't be as shallow as that of some of the better 35mm lenses, it might do the trick.

I have to say that the DOF was about the only reason that I didn't investigate the 4/3rds cameras more (I use an FF DSLR at the moment).

 

[sideshowbob]

Even on a relatively small 4/3rds sensor, you're going to get reasonably narrow DOF from f4 or so. Here's an example from an Olympus E420 at with a Zuiko 35/2.8 at 2.8.

You'll have no problems blurring a background for portraiture even at f5.6 I would think.

 

[Paul L]

Thanks to both. The 50mm is in my mind as the logical Olympus AF portrait lens, a little longer than I would like at 100mm equivalent to 35mm sensor/film.

I'm sort of torn. I don't have the talent you and others possess Ian so I and part of me says go Pentax for the portrait lenses and change the body every few years, part of me says stick with what I have and add the 50mm, the last says go back to Nikon as I like the feel and controls. Mostly down to (strictly amateur) people portraits though.

 

[cliffpatte]

It's a confusing market out there. What am I trying to achieve? Just get bakc to the digital equivalent of my old short telephoto 35mm shooting of family portraiture and I get the impression I need faster glass for DOF rather than speed per se. That and shoot more and do the E510 justice.

You can use lenses like the 85mm AF-D Nikkor on the Nikon D700 (et al) for the same effect as you would get on a Nikon F4S (for instance)

Unfortunately in the Olympus world the 35mm frame size ended with the death of the OM4ti

DOF on a 6cm square camera (like the Blad V series) is a little different again. It is to do with the relationship between field of view and depth of field based on an acceptable amount of blur (look up "circle of confusion")

 

[ultrawomble]

Thanks to both. The 50mm is in my mind as the logical Olympus AF portrait lens, a little longer than I would like at 100mm equivalent to 35mm sensor/film.

There's a handy little tool on this website that allows you to calculate equivalent DoFs across formats:

http://www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm

So, for say the equivalent of a 105mm f2.8 lens on 35mm, you'll need a 53mm f1.4 lens to obtain an equivalent DoF on a 4/3rds format. This would be pretty easy to achieve on a Micro 4/3rds camera with standard fast 50mm lens and the appropriate adapter. Don't know about a 4/3rds with a mirror box though.

An 85mm f2.8 on 35mm needs a 43mm f1.4 on 4/3rds which is just about doable with a CV 40mm f1.4 Nokton.

 

[Paul L]

I guess what I really, really want then is a Zuiko AF 42mm 1.8 (or 1.4) since 85mm was my favourite FF focal length. 105mm Ai was fabulous but a little distant for my tastes. When I bought the E510 I hoped Olympus was bring out more primes, sadly they haven't and I have not enjoyed trying MF with an old Zuiko 50mm 18

I will make a point of getting to know my kit better though before any decisions. Now I know why the 12mm to 60mm is a popular choice as it covers 24mm to 120mm equivalent and it's hobson's choice in practise.

 

[cliffpatte]

Useful link Ultrawomble, but bear in mind that that scale only works for printing at the same size. People using MF and LF cameras often print much bigger shots and the DOF is subjective based on printed image size.