Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
08-29-2011, 08:13 PM   #1
Senior Member




Join Date: Jul 2009
Location: Croydon Park, Sydney, Australia
Posts: 161
Focus Bracketing...?

I might be missing some point here, or just looking in the wrong places. However, I have the Manuals for both K-R and K-7 (new K-R here in Sydney is about the same price as a low-actuation K-7 here on the Forum, is why I'm looking at both) - and neither seems to do Focus-Bracketing.

As I have a Canon SX10 that does focus-bracketing - in all non-Auto PASM modes - in MF at settable 3 different levels of the MF selected / further / nearer - does the 3 shots at Continuous speed, 1.4fps - and Std or Custom Timer can be used handheld or tripod - I think I've just been assuming that as a P&S does that, "of course all DSLRs do that - and likely better...."

I was thinking it'd be quite useful with my new / new-usedy Pentax with Manual Lenses... This morning I was reading something about manual lenses and DOF - so wondered, "Just how do the DSLRs do the settings for Focus-Bracketing - are the settings 'sticky' or '1-off' - and how much can the before-behind the MF setting will the levels adjust to?"

So burrowed into the K-R Manual - nothing there - so thought, okay, that's entry-level, so the K-7, more midrange, will have it.... And it doesn't seem to, either...

Hmmm.... For DSLRs is this function called something else? Or there, but done in another way - so in that method's part of the Manual - or do some DSLRs - or Brands of DSLRs - just not have the function?

Maybe I'm heading my studies in the wrong direction - or being about into my doddering-era - just confused about it... Whichever - a brief explanation - or a link to one - would be greatly appreciated...!

Regards, Dave.

08-29-2011, 08:20 PM   #2
Administrator
Site Webmaster
Adam's Avatar

Join Date: Sep 2006
Location: Arizona
Photos: Gallery | Albums
Posts: 43,656
AFAIK you can't do focus bracketing, you also can't do DOF bracketing, which I would really enjoy having.

If you want to do DOF bracketing manually, just go to M mode, hit the green button, and shift the aperture and shutter speed in opposite directions. I can't see all that much utility in having focus bracketing (haven't heard of a DSLR that has it), but you could always try using the focusing ring.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)



PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

08-29-2011, 09:03 PM   #3
Veteran Member




Join Date: Mar 2011
Location: Eastern Kentucky
Posts: 416
With manual lens I bracket focus by focusing from in front of the subject,from behind the subject and then try to find the center of where the focus indicator is lit.
Jake
08-29-2011, 09:05 PM   #4
Site Supporter
Site Supporter
Chaos_Realm's Avatar

Join Date: Feb 2011
Location: Melbourne, Australia
Photos: Gallery | Albums
Posts: 1,251
I think you might be thinking along the lines of Focus "stacking" it has different terms in different places. It is a technique not a feature. You take photos, focusing on points deeper and deeper into the scene. Then in software you can blend all the photos giving you an image with greater depth of field than your set up is capable of in just one shot. This technique is very useful in macro where even the widest apertures are only giving you a millimeter of two in focus.

Here's a link


08-29-2011, 09:06 PM   #5
Site Supporter
Site Supporter




Join Date: Sep 2007
Location: Victoria, BC, Canada
Photos: Gallery
Posts: 155
DOF and focus bracketing

Both very interesting ideas - love to see them fully implemented.

Focus bracketing would be very useful in focus stacking applications (esp. macros) but would require that an initial focus distance, an end focus distance and the number of steps between be set in advance to work effectively. Nonetheless a useful feature. Even better if it could use multi-exposure and combine the image stack in-camera

DOF bracketing is already possible if you set the mode to TV (shutter priority) and use auto exposure bracketing. Limited by the number of steps and available aperture settings on the lens but using 5 steps of 2 fstops from a base of f8 would yield photos at f2,4,8,16,32 with their corresponding DOFs. I just tested this on my K20 and it does work - I always shoot in manual mode but this might just force me to use Tv once in a while.
08-30-2011, 02:05 AM   #6
Senior Member
sajah's Avatar

Join Date: Mar 2009
Location: South Korea
Photos: Gallery
Posts: 275
QuoteOriginally posted by Hornet Quote
DOF bracketing is already possible if you set the mode to TV (shutter priority) and use auto exposure bracketing. Limited by the number of steps and available aperture settings on the lens but using 5 steps of 2 fstops from a base of f8 would yield photos at f2,4,8,16,32 with their corresponding DOFs. I just tested this on my K20 and it does work - I always shoot in manual mode but this might just force me to use Tv once in a while.
I've thought about this too but haven't really tried it. Here's what I have figured out (please correct me if I'm wrong):

The problem with the approach is that the exposure also changes because the shutter and the ISO is fixed. If F8 expose properly then the F2 one will be too bright and F32 one will be too dark. But as long as it doesn't clip the histogram at both end (overexposed or underexposed) we could always darken / brighten in raw converter (practically change the ISO). Furthermore, if we clip the highlight there is no way to recover it but if it is too dark (underexposed) we have better chance to recover it in raw converter (especially with K-5 / K-r sensor).

Let say we want 1 stop difference in total of 3 exposure of DOF bracketing by using Exposure Bracketing mode. Normally the Exposure Bracketing will take 3 pictures with exposure -1 EV, 0EV and +1 EV (relative to the metering reading). But if we set Exposure Compensation (EC) to -1 EV, then it will take a -2, -1 and 0EV.

Now, let say we want to have F2, F2.8 and F4 aperture settings. We have to select an appropriate shutter and ISO that would make the camera metering to select aperture F2.8 (since we set EC to -1) and click away. The resulting images will be a -2 EV F4, a -1 EV F2.8 and a properly exposed F2. This way we can take the picture with our favorite method of metering without clipping highlight more than normally. And hope the -2EV underexposed one won't clip and can be recovered.

The method can be expanded for 5 exposures with 1 stop difference by setting Exposure Compensation to -2, or 3 exposure with 1.5 stop difference by setting Exposure Compensation to -3, and so on (but perhaps -3 is the maximum EC at least for K-x I think).

But I haven't really try this, all just in my mind so maybe I got things wrong? CMIIW

Last edited by sajah; 08-30-2011 at 02:19 AM.
08-30-2011, 06:20 AM   #7
Site Supporter
Site Supporter




Join Date: Sep 2007
Location: Victoria, BC, Canada
Photos: Gallery
Posts: 155
Of course you are right Sajah about the exposure changing. I had neglected to mention that I was assuming some post-processing to make it viable and a range of 4 stops in my example would be unrealistic for this of course. So I stand corrected - there is no real DOF bracketing and I agree with Adam that this would be a great feature to have (Pentax - are you listening?)
08-30-2011, 08:59 AM   #8
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
Technique: What I think I see being called "DOF bracketing" here should be easy to do manually in Tv mode. Shoot at a series of shutter speeds; aperture and thus DOF will adjust automatically whilst exposure remains the same. With my venerable K20D tethered and tripodded, that's simple. With a non-tetherable camera, whose controls (and body) must be touched between shots, it's trickier: the camera should be clamped into immobility.

But I'm not sure the results would be worth the effort. If the exposures are evenly-spaced, such as f/1.4@1/2000 + f/2.8@1/1000 + f/5.6@1/500 + f/11@1/250 + f/22@1/125, then stacking this series should produce a DOF the same as the midpoint, f/5.6, shouldn't it? And dynamic range wouldn't change. So maybe I don't understand the goal of DOF bracketing. What did I miss? Maybe I need more coffee...


Last edited by RioRico; 08-30-2011 at 09:12 AM.
08-30-2011, 01:23 PM   #9
Senior Member
sajah's Avatar

Join Date: Mar 2009
Location: South Korea
Photos: Gallery
Posts: 275
QuoteOriginally posted by RioRico Quote
Technique: What I think I see being called "DOF bracketing" here should be easy to do manually in Tv mode. Shoot at a series of shutter speeds; aperture and thus DOF will adjust automatically whilst exposure remains the same. With my venerable K20D tethered and tripodded, that's simple. With a non-tetherable camera, whose controls (and body) must be touched between shots, it's trickier: the camera should be clamped into immobility.

But I'm not sure the results would be worth the effort. If the exposures are evenly-spaced, such as f/1.4@1/2000 + f/2.8@1/1000 + f/5.6@1/500 + f/11@1/250 + f/22@1/125, then stacking this series should produce a DOF the same as the midpoint, f/5.6, shouldn't it? And dynamic range wouldn't change. So maybe I don't understand the goal of DOF bracketing. What did I miss? Maybe I need more coffee...
You need more coffee

I mean, we're talking about bracketing, which is not necessarily for stacking purpose. Focus bracketing can be used for stacking DOF but I don't think that's what the OP wanted. Like exposure bracketing, you get 3 picture of different exposures and you can choose which one you like. The OP wanted Focus bracketing for similar purpose, so that he can get to choose between 3 different focus point, one of which, hopefully, focus correctly

Now the DOF bracketing purpose, for me at least, is so I can get 3 pictures with different DOF and choose which one I like. Most of the time I like to use my fast lenses wide open, but sometimes I want more sharpness and or more DOF. It's nice to have a choice! But honestly I haven't really tried the method myself
08-30-2011, 02:57 PM   #10
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
QuoteOriginally posted by sajah Quote
You need more coffee
Unfortunately my cardiologist insists on minimal stimulants, so I only get to drink DEPRESSO -- decaf espresso. Ah well... And that's my excuse for occasional stupidity. One of my excuses, anyway.

QuoteQuote:
Now the DOF bracketing purpose, for me at least, is so I can get 3 pictures with different DOF and choose which one I like.
So maybe try the method I mentioned above. At least it costs nothing. [/me counts out a few pennies, looks forlorn]
08-30-2011, 04:54 PM   #11
Senior Member




Join Date: Jul 2009
Location: Croydon Park, Sydney, Australia
Posts: 161
Original Poster
Adam - Thanks for making it clear that these cameras don't focus-bracket. It does seem odd - particularly for MF - that they don't. Maybe Pentax DSLRs are just so good, you're meant to get perfect focus on every shot!


Bjake - With my 30x Fuji HS10 (doesn't focus-bracket) - which is a bad "focus hunter" at anything past two-thirds zoom, I change to MF, and as the camera has on-barrel zoom and focus rings - find I can "rock" the focus with the ring, each side of "on" until it "centres" the focus. Can do "under and over" shots to sort-of bracket that centring.


Chaos_Realm - No, nothing to do with stacking (where 2 or more images can be used on Layers in PP.) The Canon SX10 can be set so it takes 3 separate shots (at 1.4fps) - with 1 press of the shutter. These are in order of 1 at the current MF setting, 1 further away than that, and 1 closer. The "over and under" amounts have 3 settable distances. See Diagram from the Manual below.

You can use the Self Timer at 2sec to fire the 3 shots handheld while avoiding inadvertent camera movement from pressing the shutter full-down. On a tripod I incease the delay to a Custom Timer setting of 5-sec, to allow any vibes a bit more time to fade.


Sajah - You gottit! "...Like exposure bracketing, you get 3 picture of different exposures and you can choose which one you like..." - that's exactly what it does. And, instead of AEB's adjustable exposures - the over-under distances are adjustable.

Re the AEB with Pentax DSLRs - apparently it's assumed to be hand-held - as the 3 (3 or 5 with K-7) shots can't be fired with Timer only - the shutter has to be physically held down until the 3 / 5 shots fire. So in the case of AEB - you can't do tripod mounted sequences with the Timer to avoid vibes, if say doing it to get sets for HDR.

Thanks to all for the explanations.

Regards, Dave.

(Attrib. Canon SX10 IS Manual, Page 130.)
Attached Images
 
08-30-2011, 05:07 PM   #12
Veteran Member
Laurentiu Cristofor's Avatar

Join Date: Nov 2009
Location: WA
Photos: Albums
Posts: 3,044
QuoteOriginally posted by exwintech Quote
Adam - Thanks for making it clear that these cameras don't focus-bracket. It does seem odd - particularly for MF - that they don't. Maybe Pentax DSLRs are just so good, you're meant to get perfect focus on every shot!
MF usually means manual focus, but you seem to use it to refer to something else - what is that?
08-30-2011, 06:36 PM   #13
Senior Member




Join Date: Jul 2009
Location: Croydon Park, Sydney, Australia
Posts: 161
Original Poster
Laurentiu Cristofor - In the context in which you quote me - "....Adam - Thanks for making it clear that these cameras don't focus-bracket. It does seem odd - particularly for MF..." - yes, I was indeed referring to Manual Focus.

I do now see that the "particularly for" part might have made the reference seem vague.

What I was doing was referring to Focus Bracketing in the context I'm used to it - that is, with the camera I have that does it, the Canon SX10.

The camera has Manual Focus in all shooting modes other than Auto. And it will Focus Bracket in MF in P-A-S-M.

So one can wander about taking the usual shots in Shutter or Aperture Priority - but where needed - say, aim up into a tree at a bird - which has leaves / branches nearby - and the AF won't lock onto the bird only. At that point, press the "^" arrow on the 4-way pad, to change to MF (Manual Focus.) The ring around the 4-way pad rotates to adjust the MF.

It's quite nifty - but on a P&S Zoom - not as tack-accurate as those long-throw 260-degree Focus Rings on Takumar primes... So you can, hand-held - get pretty close to spot-on "selecting out" your bird from the leaves and twigs - but - if you've preset the MF with Focus Bracketing (see the Diagram) - with one press of the shutter button you get 3 rapid shots - at the MF chosen - a bit further, and a bit closer.

As you can see in the Diagram - which shows the "closest" setting - the 'further' and 'nearer' distances are pre-settable. And that is "sticky" - change Modes - Aperture to Shutter Priority, or either of those to Manual mode - selecting MF will still retain Focus Bracketing at the 1 of 3 distances preset. (Also after turning the camera Off and back On.)

Therefore - Focus Bracketing is a function that goes with, and is particularly useful in - Manual Focus.

In Shutter Priority it's useful when the target is shifting position - you can do 3 main shots - but get 9 images, 3 at different focuses for each main shot - in under 10-seconds, with the SX10. (The SX20 is somewhat slower.)

The SX10's Continuous Shooting is a leisurely 1.4fps. My Fuji HS10 does up to 12.5 fps Continuous - but doesn't Focus Bracket. A camera that could Focus Bracket 3-shots at even the HS10's midrange 7fps would be rather nifty...!

I was rather hoping that DSLRs could do that, or better... Which is why I asked.

Regards, Dave.
08-30-2011, 09:26 PM   #14
New Member




Join Date: Nov 2010
Location: Montreal
Posts: 17
Isn't the idea of DOF bracketing the same as Lytro's idea of "multiple focus". In the end, if dSLR manufacturers would implement the functionnality of DOF bracketing and it would create a single image of new format (which you be a flash format for viewing online), it would surpase the quality of Lytro's images ??

Edit: Never mind, just thought of it, the DOF is still having the focus at the same position, only the background or foreground will have a slight chnage in focus.

Last edited by kaarde; 08-30-2011 at 09:33 PM.
08-30-2011, 10:37 PM - 1 Like   #15
Veteran Member




Join Date: Jan 2010
Location: Vancouver, BC
Posts: 1,421
DOF bracketing, who'd thunk it? In the film days, you just had to look at the lens hash marks, remember the aperture you shot at and there it was, your depth of field. Not enough, too much, just change your aperture and re-shoot. Holy crap, it works with DSLR too!? C'mon people, learn to use the tool that's at hand, instead of wishing for some totally redundant, novelty features found on a (no user input necessary) P&S camera. DOF bracketing... :ugh:
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, dslr, dslrs, function, k-7, k-r, levels, mf, photography, settings
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Firmware Request: Focus bracketing secateurs Pentax K-5 9 02-24-2011 07:00 PM
Bracketing? DaveHolmes Troubleshooting and Beginner Help 6 10-14-2010 01:57 AM
Bracketing: other than EV Bill L Troubleshooting and Beginner Help 9 09-25-2010 06:00 PM
Exposure Bracketing on the K-x noahpurdy Troubleshooting and Beginner Help 7 12-26-2009 10:28 PM
K110d and Bracketing warrenstilwell Troubleshooting and Beginner Help 4 11-24-2009 08:31 PM



All times are GMT -7. The time now is 07:26 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top