How do you envision depth of field with a RF camera?

[raid]

Using an SLR, we can readily see the DOF and bokeh of a lens by using the DOF preview. How do you go about controlling DOF with RF lenses? Each focal length and aperture chosen may result in a different DOF. In the most recent images that I uploaded to the gallery, I failed in predicting the DOF/bokeh. I thought that the background would be better diffused and less showing, but the wall shows.

I recall Roland informing me at one stage that a 85mm/1.5 has similar/same DOF as a 100mm/2. Knowing such facts helps us in better choosing our lenses.

What do you do to master DOF with a RF camera?

 

[ethics_gradient]

Using an SLR, we can readily see the DOF and bokeh of a lens by using the DOF preview. How do you go about controlling DOF with RF lenses? Each focal length and aperture chosen may result in a different DOF. In the most recent images that I uploaded to the gallery, I failed in predicting the DOF/bokeh. I thought that the background would be better diffused and less showing, but the wall shows.

I recall Roland informing me at one stage that a 85mm/1.5 has similar/same DOF as a 100mm/2. Knowing such facts helps us in better choosing our lenses.

What do you do to master DOF with a RF camera?

Being a straight SLR shooter for 4+ years, don't think I've used the DoF preview more than 2-3 times. I just do a rough guestimate in my head and more than nine times out of ten I'm satisified with the results.

 

[raid]

That's a good one.
I will here then state again ..... that I am referring to RF cameras using film.

 

[Rob-F]

To make sure the entire depth is in focus, you use the DOF scale on the lens barrel. You need to select an aperture small enough that the aperture marks on the scale span the entire distance range, near to far.

To make sure that the background is out of focus, I use the widest aperture I can get away with, and make sure the mark corresponding to the distance to the wall is as many stops (on the scale) away from the distance focused upon as possible. I feel it is important to use the widest aperture you can, as things in the background tend to remain surprisingly recognizably in focus until they are really, really out of focus. With modern highly corrected lenses, the effect is even worse.

I hope that is clear . . .

 

[Morca007]

I don't find SLRs very useful for previsualizing DOF either. It's all mental.

 

[Jamie Pillers]

I'm with Rob... use the dof scale on the lens... and experience. 🙂

 

[Keith]

You can't really and this is one area where the SLR is far superior IMO. This problem and lack of accuracy when framing aren't always important but sometimes limiting when using rangefinders ... but then there's not that darned mirror black out to deal with!

 

[Al Kaplan]

Probably the two things that have the most effect on depth of field are the lens to subject distance and the absolute aperture of the lens, that is, the diameter of the diaphragm opening.

If you draw two lines from the subject to both sides of the aperture you'll see that the larger the aperture and the closer the subject the more these lines diverge. The more the divergance the fuzzier the image is at that point.

Bokeh gets more complex because it's also affected by whatever aberations the lens might have. Most lenses suffer from some degree of spherical aberation, and this can get complex, with radial lines not being brought to the same plane of focus as circumferential lines. That is, a photo of say a window screen or brick wall might have vertical lines sharper than horizontal lines in one area of the photo, but the reverse elsewhere in the picture.

My own feeling is that if you want great out of focus areas buy lenses designed for motion picture cameras and shoot them on an SLR. If you want to use one of those old fashioned film eatin' rangefinder throwbacks to another era make sure that you have great composition, interesting lighting, and dynamic subject matter. Make the photo so exciting that nobody will notice that you used a Sonnar formula lens with simply horrid bokeh.

 

[ReeRay]

Shooting a Contax G2 (no DOF scale on the lens barrel) I HAVE to use the DOF scale printouts that I carry with me everywhere.

After a while I now find I can envisage the effect from memory.

Fortunately I've only got 3 lenses to remember! 🙂

 

[raid]

These are all useful suggestions and explanations. I mainly use the DOF scales on the lenses.

Al: Why do you refer to Sonnar lenses as lenses with horrid bokeh? I mean, is this really a fact or is it your feeling?

 

[Keith]

These are all useful suggestions and explanations. I mainly use the DOF scales on the lenses.

Al: Why do you refer to Sonnar lenses as lenses with horrid bokeh? I mean, is this really a fact or is it your feeling?

There was a thread recently that had an image in it from a 1.5 Sonnar that totally ended any Sonnar lust I may have had ... the bokeh was harsh to say the least!

 

[lorriman]

With focus distance, aperture and background distance all in the mathematical mix I reckon it is impossible except in the case of idiot savants. Since the degree of oof background is an important aspect of my own pics I use stopdown SLR camera and lenses for this purpose since what you see on the ground glass is pretty much what you'll get. Rangefinders are for holiday pics and photos that where oof areas are unimportant.

FD lenses can be hitched to a (cheap) Canon A-1 which has a lever that gives stop-down metering on any FD lens. No having to press a dof-preview button: hurrah! And the mount is obsolute and can't be converted for digital so the lenses are cheap. My FL55/1.2 cost £42.

 

[Rob-F]

Al: I wonder why you say that lenses for motion picture cameras are the best for OOF backgrounds? They are designed for a format no larger than 18 x 24mm, with correspondingly shorter focal lengths (unless they were made for 70mm film--not cheap), so should have greater DOF and sharper backgrounds.

Agree, or disgree?

 

[Mudman]

Sometimes if the subject isn't moving much, I'll focus on the far area and the near area that I want to be in focus, and then use the DOF scale on the lens to figure out the aperture. I've done this with SLRs as well since the screen gets so dark at f16 or f22. Bokeh is anyone's guess.

 

[raid]

There was a thread recently that had an image in it from a 1.5 Sonnar that totally ended any Sonnar lust I may have had ... the bokeh was harsh to say the least!

Keith,

I missed that thread. I find my Zeiss Jena 5cm 1.5 to have butter smooth OOF rendering. The same applies to the Sonnar 5cm 2.0.

 

[splitimageview]

Sonnar and harsh bokeh are oxymorons. 😉 I have thrown all sorts of difficult backgrounds at my CZO 50/1.5 and it's anything but harsh...

 

[rya]

I rely on experience for judging DOF. I also got a free application for my phone called Bokeh that computes DOF and hyperfocal distances, but found that it is interesting as a rough guide but in practice I was better off at just testing lenses and remembering what each aperture looks like. Sometimes I am wrong, but available light levels dictate my aperture decisions often enough that I am not too worried about it.

I started photo with SLRs but never found the preview that useful, so I got used to assuming what the results would be.

I like all the bokeh and focus transitions my only two m lenses produce, though, so maybe I would be more careful if I did not.

 

[gb hill]

Please don't take this the wrong way, but if one would quit spending week after week whoring around with several different lenses & just take the time to get intimate with one lens & become aquainted with it's characteristics. (will mean having to shoot many rolls of film). To me this is the only real way to know.

 

[Keith]

Keith,

I missed that thread. I find my Zeiss Jena 5cm 1.5 to have butter smooth OOF rendering. The same applies to the Sonnar 5cm 2.0.

I remember now that it was the thread about 3D looking images that Joe started .... the bokeh in the bench shot he posted was a little ugly but with the Epson's crop factor maybe not a fair assessment of the lens's true character!

 

[Gabriel M.A.]

I don't find SLRs very useful for previsualizing DOF either. It's all mental.

So that's why they call me that 😉


To answer Raid's question: if I couldn't previsualize it, I wouldn't be able to do the shots I do at close range, "wide open".

At distances farther away than 5 or so meters, it gets trickier with long focal lengths.