DOF And The 45 mm

I've been playing with my new 45 mm lens on my omd and realise how much depth of field control there is.  I've taken some portraits at f1.8 and can see that they might have been better with a wider dof.  I'd be interested in what f stop other people are using for portraits with this lens.

Dan

I don't think there's simple solution as it'll depend on camera to subject distance, the framing you want. I think it'll help you most if you shoot some practice shots at different distances and framing and decide what works best for you. For example with the same settings you'll get different results if you're shooting a tight head shot or a full body shot taken from much further away.

Here's one of the photos.

Good advice.   A DOF calculator might be helpful to visualize the variations possible.

Cambridge In Colour DOF calculator

--
...Bob, NYC
http://www.bobtullis.com
"Well, sometimes the magic works. . . Sometimes, it doesn't." - Little Big Man
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If I want really sharp output, but average DOF, I use about 4.8...if I need shallow DOF, I use something in the low 2.0s. I like to take advantage of the sharpness of the lens - if I get something too sharp for portraits, I can adjust it later in PP.

Do you think that the photo that I posted is too much out of focus?  (Photo is in my first reply to the original post.)

Dan

Depends entirely on the distance to subject and the distance between the subject and background.  For example, if you're shooting a head shot at f/2 and the subject is against a wall or backdrop, you'll get nice BG blur.  But if your subject is standing outside and the nearest object is 300 yards away, the BG will be obliterated.

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Here is a group of portraits I shot with the 45. I believe most are f2.2. Some could arguably use a touch more DOF, but not one viewer has complained. The EXIF is intact on these images, but it is not displaying due to the fact they were posted before the forum software change. You can download them and view the exposure parameters or use a browser plugin to view the EXIF data directly:

OMD/Oly 45mm portrait-athon

1.8 is very thin DOF on the 45 if you are near the subject. You also generally need a ND filter if you are outdoors to stay within the OMD's 1/4000th top shutter speed.

Matter of taste, but I would say the DOF is too narrow in that pic.  I'd aim to have both eyes in focus.

That's my impression too.  Maybe 2.5?  I'm trying to get to know this lens.  I guess the best way would be to experiment, but I'm asking for wisdom from the forum.

Dan

Thanks for the examples, nice work.

Dan

Depends on the framing, the distance, and what you like. You have to decide yourself.

As others have said, it depends. There is no single f-stop that will work in all cases.  Different camera to subject distances, subjects and desired focus areas will require different f-stops.

--
http://fruminousbandersnatch.blogspot.com/

When I'm taking an indoor or even an outdoor available light shot although I'll probably be using aperture priority I'll be monitoring the ISO setting and the shutter speed too because if my choice of aperture causes the ISO to rise too much or the shutter speed to fall too much the chances that I'm going to get the shot that I want may fall.

Taking your above shot as an example I wonder if using a smaller aperture to increase the DoF would have caused the shutter speed to drop to the point that camera or subject movement could have been an issue? If it could/would have caused a probelm it may have been better to keep the wide aperture and instead open up the framing a little by stepping back a pace or two and increasing the DoF that way?

Of course if you use flash you wont have this problem

PS. I forgot something...

I don't get everything right first time and if I think that camera settings may be an issue I try and take more than one shot... You don't have to fire off shots machine gun style but no one could expect to get the DoF spot on every single time so why not take a couple of shots at different apertures, for example start at f1.8 and then quickly stop down to f2.8, f3.5 etc. and pick the one that looks best as the keeper?

Thanks for the good suggestions, especially about monitoring other settings.

In this case stepping back would have been difficult.  I was seated across the table and took several photos using the tilt screen.  She knew I was taking her photo, but she probably didn't realise how many I had taken.  So I was able to get something more candid.

Complex business this, getting the perfect shot.

Dan

Thanks woofwoof.  It's people like you that make this forum so great.  Thanks to everyone else as well.

It's midnight here, time for bed.

Dan

I think that in the case of candid grab shot few would exepect perfection first time and every time and in this case I personally would have been very happy with the result that you got Or make that very very happy

Increase the distance, and make a crop.

If you choose 2.5, then the background would be sharper also, and probably you dont want this.
If you leave 1.8, but choose twice the object distance and then crop at 50% size, then you get twice the DOF, that means you get as much DOF as if you had stopped down to 3.6 .
The background distance must be infinity (practically this means 5 or 10 times more than the object distance) and in this case the background blurring is the same as before.

If you dont want to crop then use a 100mm Tele at f3.6 and double the distance.

Peter