Pre-Focusing technique

[ruben]

I think it was some week ago, our friend Franks recalled the use of the prefocusing technique for fast street shooting.

Today I gave it some thinking and theoretically, at least for me, it makes a lot of sense. If the thing really works, that's great news for users of slow to operate cameras, like the Kievs or Contaxes. But for owners of good Aperture Priority Auto Exposure cameras, for instance the Electro series, this may be golden news. Just frame and presto. Wind and shoot. Definitely I will give it a good try in my next shooting op, this Friday.

Set your Electro for 3 meters at f/16 and you will have a depht of field ranging from some 1.7 meter up to some 20+ meters - a great ratio. Occasional very close subject? = occasional fine grain manual focusing.

I think I am describing this technique in its most simplystic manner, almost idiotically. Therefore I would like to ask for help with some questions:

a) the f/16 is at the extreme side of the scale, will it deteriorate the image quality for that reason ?

b) what about the aesthetics and framing of images, in which everthing is in focus ? I guess some things change once you are denied the out of focus side.

c) Ok, if I set my camera at f/16 and at 3meters, as described, a person standing at 3 meters will be in critical focus. But how he would look like if he stands at 2 meters or 4 meters ?

d) Am I missing something (or a lot) ? :bang:

Highly Important
I invite everyone who has used or still uses this technique to post image samples for me and others to learn from.

Cheers,
Ruben

 

[RML]

The only thing that you may be forgetting is shutter time. Depending on the light, f16 may give you rather long shutter times.

 

[ruben]

The only thing that you may be forgetting is shutter time. Depending on the light, f16 may give you rather long shutter times.

In my case it will be no problem at all, as I customarily carry two cameras or nothing. One loaded with ISO 200, the other ISO 800. So I will most of the times be shooting at high speeds.

 

[telenous]

Ruben,

I use hyperfocal a lot, not just with Yashicas but with any rangefinder camera. You suggest focusing at three meters and then everything in the range of 1.7 to 20 meters will be in acceptable focus. I do it a little differently - I set the infinity at the selected aperture (lets say this is set at f16) and then everything from 2m to infinity will be acceptably focused. There are obvious advantages with either technique, but the idea is the same.

As far as I know f16 always degrades image quality due to diffraction but not in objectionable way. In my opinion the compositional effect, in terms of depth of field, resulting from the choice of aperture is more important than any purported or actual loss of detail due to diffraction. ('Sharpness is a bourgeois concept' etc.etc.)

I have lots of photos taken on hyperfocal, you will forgive me if I don't post right now, most of them seem to be on the hard drive of my old computer. I 'll choose some samples and post later.

PS. Apologies - as I 'm writing this I realise it is posted in the Yashica forum. I 'm a newbie when it comes to Yashicas, I have only bought one very recently, so I don't have any photos from the camera yet. But, no doubt, I will very soon ;-)

 

[utku]

ruben,

visit this page; http://www.dofmaster.com/dofjs.html

you'll see that for 45mm at f/16, if you focus your camera in around 4 meters you'll get the highest dof possible..

if you focus to 3m, theoretically you'll get everything from 1.76 to 10 meters in focus.. the objects out of this zone will be blurry, and will get blurrier depending their proximity to this zone...

if a person stands on 2m, he'll be blurry, if he's on 4m, he'll be sharp as if he's in 3m..

I don't use pre focusing, since I'm quicker in controlling Yashica, but it makes no difference if you use this technique correctly.. it is quoted that HCB said : Sharpness is a bourgeoise concept..

 

[ruben]

Thanks TELENOUS, it is not important at all with which camera to made the hyperfocal images, I need to see and get impression.

Thanks DAVE, for your posted images. A couple of factors become clearer in an everything-sharp photo.

I still would like very much see more pics, including some with the main subject away from the critical focus point.

 

[ruben]

Hi Utku,
Thank you for your posting with that highly usable link. I think you are right, the 4 meter setting seems more practical.

Now what will happen with combining both the image degradation of the f/16 and "acceptable focus" instead of critical focus. Will something be left ?

Cheers,
Rubeh

 

[ruben]

Well, after refreshing my eyes at RFF Galleries and Flickr, I come to the conclusion that the image possible degradation by the prefocusing technique is not the main issue. The main issue seems to be composition.

There are images where the background complements or armonizes with the subject, and here the everything-in-focus works, and there are images were the in-focus-background is highly distracting from the subject, unrelated and confusing. Therefore it seems the hyperfocal technique for street photography should be seen just as one technique among others, to be used selectively. Not for free machine-gunning.

But I started from the issue for speeding up the camera manipulation vis a vis moving subjects, and by now I end with the need of slowing my mind pre-visualization of the image, in addition to getting acquinted with a new camera. No shurtcuts in the climbing, next Friday I will take it easy.

Nevertheless, in a further thought, it seems a great idea that taking into account the abovementioned restrain, the cameras would be preset to hyperfocal shooting as a standard proceeding, either to follow or depart from.
Cheers,
Ruben

 

[Wayne R. Scott]

c) Ok, if I set my camera at f/16 and at 3meters, as described, a person standing at 3 meters will be in critical focus. But how he would look like if he stands at 2 meters or 4 meters ?


Cheers,
Ruben

Here is how a person looks at one meter when 40mm lens is focused at 3 meters. The guy framed in right center is at 3 meters.

Wayne

 

[ully]

Ruben,

I use hyperfocal a lot, not just with Yashicas but with any rangefinder camera. You suggest focusing at three meters and then everything in the range of 1.7 to 20 meters will be in acceptable focus. I do it a little differently - I set the infinity at the selected aperture (lets say this is set at f16) and then everything from 2m to infinity will be acceptably focused. There are obvious advantages with either technique, but the idea is the same.

As far as I know f16 always degrades image quality due to diffraction but not in objectionable way. In my opinion the compositional effect, in terms of depth of field, resulting from the choice of aperture is more important than any purported or actual loss of detail due to diffraction. ('Sharpness is a bourgeois concept' etc.etc.)

I have lots of photos taken on hyperfocal, you will forgive me if I don't post right now, most of them seem to be on the hard drive of my old computer. I 'll choose some samples and post later.

PS. Apologies - as I 'm writing this I realise it is posted in the Yashica forum. I 'm a newbie when it comes to Yashicas, I have only bought one very recently, so I don't have any photos from the camera yet. But, no doubt, I will very soon ;-)

I use the same method. I think it was manual focus forum that I read that tip
Works great for older lens with the aperature ring and markings. Unfortunately the new lens don't have this available.

Cheers

 

[ruben]

Here is how a person looks at one meter when 40mm lens is focused at 3 meters. The guy framed in right center is at 3 meters.

Wayne

Hi Wayne, thanks for addressing the issue.

Are you trying to say that within the hyperfocal depht, subjects at the near-to-us side of critical focus are going to suffer more than those beyond the critical focus ?

Cheers,
Ruben

 

[markinlondon]

I often zone focus with 35's, Ruben and yes, the depth of focus is greater behind the point of focus. I'm looking here at the scale on a 40mm lens (Pentax K, not rf, forgive me) and, when focused at 3m at f8 the depth is from about 2m to about 8m. This is a rough estimate as the scale on this lens is quite sketchy.

 

[Toby]

Ruben if you shoot with two cameras why not set one as close focus and one as an infinity to x focus. This was a common method in the sixties and I believe Koudelka used this for a while to the point where he had two 35's with the focus rings taped to his preferred settings - so you'd be in good company

 

[sbart]

I often zone focus with 35's, Ruben and yes, the depth of focus is greater behind the point of focus. I'm looking here at the scale on a 40mm lens (Pentax K, not rf, forgive me) and, when focused at 3m at f8 the depth is from about 2m to about 8m. This is a rough estimate as the scale on this lens is quite sketchy.

I knew I read about this somewhere, and pulled the book off my shelf. From the very excellent The Bare Bones Camera Course for Film and Video by Tom Schroeppel, pg. 19 I quote:

You always have less depth of field in front of your point of focus than behind it. This is especially noticeable at distances of 25 feet or less. At these near distances, you can usually figure on your depth of field extending approximately 1/3 in front and 2/3 behind your point of focus.

 

[Wayne R. Scott]

Hi Wayne, thanks for addressing the issue.

Are you trying to say that within the hyperfocal depht, subjects at the near-to-us side of critical focus are going to suffer more than those beyond the critical focus ?

Cheers,
Ruben

Yes Ruben, as has been stated above by others. Depth of field for critical focus is affected by several things. The f-stop chosen, the focal length of the lens, the format size (i.e. 35mmm 6x6, 4x5, etc.) the distance of the critical focus point, the C.O.C. (circle of confusion) of the lens, the distance at which the final print is viewed, the degree of enlargement of the final print, and the subjective nature of what the viewer will accept as critically sharp.

I don't know if this helps or hinders you.

Wayne

 

[sf]

F16 WILL deteriorate image quality to some degree, depending on the lens architecture, quality of the glass, and aspects of the lighting in the scene.

I find no trouble with images in which everything is in focus. Then, it simply becomes an issue of composition that determines the framing.

If you set it for 3 meters at f/16, the person at 3 meters will be in sharp focus, then perhaps a meter in front of that person, and many many meters behind them (depending on lens architecture). For a 15mm heliar, f/16 equates to almost pinhole like DOF, while F/16 on a 90mm summicron does not.

When I go out with prefocus in mind, I set it for maybe 5 meters out and F11 on my 45mm lens. That gives me the ability to get most everything from 2 meters out in pretty sharp focus - sharp enough. This is for street work. For landscapes, I set the focus to work with my framing. If I want a close foreground object to be in focus, I set for maybe 10 meters out and F/32. I have learned from working with the RF645, that even f/32 doesn't vastly deteriorate image sharpness - it only lowers contrast somewhat.

If I want a scene with all-round good focus, I set it at f/16 and focus for 1/3 of the way into the scene. This works with Delta 3200 @1600.