Automated Hyperfocal Focusing

<p>I was playing with old manual-focus lenses for my film cameras the other day. You know, the ones with solid metal barrels and beautifully engraved depth of field indicators? Ah, just to be able to select Aperture Priority, set the aperture, and the computer focuses the lens at the exact distance needed. Or select Program, focus on an object in the foreground, lock, focus on something in the background, lock, then the wondrous digital imager in your hands makes the exposure while keeping both objects within the depth of field. OK, I guess then it would be zone focusing. But are there any modern cameras that can do automated hyperfocal focusing, or anything close to it? How hard would that be to implement in their software/firmware?</p>

<p>Canon have such on their old film range it is called DEP. This is not the same as A-DEP. I believe if you try it you will like it ... sadly Canon have released this comittment from their range for obscure and unbelivable reasons</p>

<p>Yoshio, I vaguely remember something about DEP on an old Canon film camera. Yes, that did sound much more useful than that A-DEP mode. With the amount of automation that is built into new cameras, it seems that it would be easy for somebody to enable a DEP mode under which a user could choose an aperture and have the lens lock onto the hyperfocal distance at that aperture. Of course, it could get a little more complicated than that. For example, you would probably want to scroll through various combinations of f-stops and shutter speeds, should the camera choose a combination that is difficult to hand-hold.</p>

<p>When you select manual focus, the Panasonic LX3 has a yellow DOF bar on the right side. Just change the aperture and focus point so the yellow bar extends to infinity, and you have set hyperfocal distance.<br>

I thought traditional DOF preview was easier and more effective than DEP or A-DEP, but perhaps I just never got used to it.</p>

<p>My Elan 7n has DEP.  I think my 1n has it too.  I don't think any of the digitals have it.  Great feature!  It's boggling why Canon would believe this feature wouldn't be enjoyed/appreciated by digital photographers!</p>

<p>DOF preview is OK, don't some new (digital) cameras still have it? However, it was even easier to do it the traditional way, by adjusting the aperture and focus rings; twist, and you have instant focus.  But new lenses don't have very useful depth of field markings, or aperture rings, any more.</p>

My Pentax K10D has DOF preview, both optical and digital. I agree, however, that an automated hyper-focal mode would be great, or at least a return to marking the dof settings on the lenses. With today's autofocus lenses that have such short focus rotation, that may not be practical. By that, I mean that, in the old days, it could take almost a full rotation of the focusing ring to go from close focus to infinity. Now, the focus ring on an AF lens turns 90 degrees or less.

 

If they provided an automated h-f mode, though, I think that there would be a great many users (especially newbies) who don't understand it. Just look at how often questions appear on this and other forums that show the user really doesn't even know what dof is, let alone h-f focusing. There would be a lot of people returning their cameras or sending them for service, complaining that their camera just doesn't focus in h-f mode.

 

Paul Noble

<p>A-DEP is somewhat bogus, because there is no definitive border between acceptable in-focus and out-of-focus. It is entirely subjective. The actual plane of focus is infinitely thin. Some lenses render slightly out-of-focus areas better than other lenses render areas within the nominal DOF. The circle of confusion also changes with format (sensor size) but everybody should know that. What I'm saying is that it also changes with lens quality.</p>

<p>TM<br>

the method for using DEP on the older Canon cameras is to focus first on near then far desired distances. The camera then locates the lens focus to be at a hyperfocal distance and also sets what aperture it is programed to be the acceptable Depth of field. Since this may vary for photographers desire they incorporated a shiftable aperture to enable the photographer to dial in a bigger number such as f16 if camera chooses f11.<br /> This was from EOS 630 onwards which was a 1989 camera.<br /> I am pleased to see how far we have gone in functional camera automation today.<br>

yoroshiku</p>

<p>Yoshio, thanks for the explanation, however I think you are misusing hyperfocal.  Only one hyperfocal distance

exists at a given distance and aperture. It is related to infinity, not to DEP near and far points.</p>

<p>Bill</p>

<p>perhaps ... what then is called the system where by you focus on the subject then confirm the focus near and far by using the (now depreicated) markings on the lens.</p>

<p>I checked with an english language source (http://en.wikipedia.org/wiki/Hyperfocal_distance) and it seems to me reading it that this is a term which is a little rubbery.</p>

<p>"what then is called the system where by you focus on the subject then confirm the focus near and far by using the (...) markings on the lens."<br>

That would be zone as opposed to hyperfocal focusing. Two methods to achieve (more or less) the same goal.</p>