Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-10-2015, 08:25 AM   #16
Senior Moderator
Loyal Site Supporter
Nass's Avatar

Join Date: Aug 2009
Location: The British Isles
Photos: Gallery
Posts: 2,251
Ahhhh, I see - thanks for putting me right

04-10-2015, 09:36 AM   #17
Senior Member




Join Date: Jul 2010
Posts: 271
Canon EOS (do not remember the model of the 35mm film body) used to have focus-bracketing.

-----
QuoteOriginally posted by jonby Quote
And yet to my knowledge this has never been done on those systems.
04-10-2015, 11:52 AM   #18
Senior Member




Join Date: Nov 2013
Posts: 153
QuoteOriginally posted by Prakticant Quote
Canon EOS (do not remember the model of the 35mm film body) used to have focus-bracketing.
Thanks for highlighting this - this confirms that it is technically possible then, at least with that system. Would be interesting to know how well it worked. I'll look into it.

QuoteOriginally posted by dakight Quote
I intend to experiment with focus stacking and I suspect it will be tedious at best to manually dial in precise increments from front to back. I don't know how precise those increments even need to be so it will be a learning experience for me. A simple focus bracketing function implemented in the camera body would take a lot of the tedium out of the process.
Yes I have done some manual focus stacking myself and it can be fairly-to-very tedious, depending on how many shots you need to take (which you won't know without experimenting). It's a lot easier with an old manual lens with a decent focus throw and smooth action, but difficult to impossible with a lot of AF lenses, which is one reason why this feature is needed. Automated focus stacking would certainly be a useful function, though actually my main desire is for a system which allows me to guarantee getting optimum focus in a given situation. Two different uses, similar methods.

QuoteOriginally posted by Nass Quote
one of the most interesting things out there is magic lantern, a 3rd party adding all sorts of interesting functionality to Canon cameras... including focus stacking
I wasn't aware that Magic Lantern did focus stacking. More weight to the argument that there's no technical reason not to implement this. If you can do focus stacking, you can do focus bracketing.

QuoteOriginally posted by Nass Quote
I've been wondering why camera manufacturers didn't have more functionality inside bodies for years now, and all I can think of is that it's some sort of in-body processing power/memory limitation, possibly a hangover from the old days.
It's hard to believe that it's anything to do with lack of processing power or memory, when some cameras can process six 36MP raw images per second. Practikant believes that has been done before - around 20 years ago by the sounds of it. I'm convinced that the reason this facility isn't part of the feature set is down to something other than technical limitations. In the case of focus bracketing, my guess is that they simply don't like to admit that their AF systems aren't accurate all the time.

QuoteOriginally posted by stevebrot Quote
The idea that the body knows exactly how the lens is doing its work is one of the most common misunderstandings of users on this site who are seeking to tweak their AF systems.
I don't think this precludes the implementation of a focus bracketing system. As I said before, if it's possible to tell the AF system to focus slightly forward or backwards of the position that the camera believes is in focus (as with fine AF adjustment), then it's possible to automate taking two or more shots with the focus shifted a certain amount forwards and a certain amount backwards. Determining what this amount should be is perhaps where the difficulty lies, but even if this were set manually that would be something.
04-10-2015, 12:15 PM   #19
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,424
QuoteOriginally posted by jonby Quote
then it's possible to automate taking two or more shots with the focus shifted a certain amount forwards and a certain amount backwards. Determining what this amount should be is perhaps where the difficulty lies, but even if this were set manually that would be something.
Yes, the devil is in the details and in this case the details are pretty significant. A "tick" of the AF system (manual focus too, for that matter) can be pretty course at distance or with high magnification. How much depends highly on lens.


Steve

04-10-2015, 12:33 PM   #20
Senior Moderator
Loyal Site Supporter
Nass's Avatar

Join Date: Aug 2009
Location: The British Isles
Photos: Gallery
Posts: 2,251
Turns out that Magic lantern actually does something like you describe Lowell - "rack focus".
QuoteQuote:
Step-by-step:

1. Pick the end point of rack focus by focusing on it (manually or with AF).


2. Configure focus parameters (step size and delay). Different lenses may require different parameters.


3. Open the Focus menu, go to Focus End Point and press Set to zero it out.


4. Pick the start point by focusing on it with the LEFT/RIGHT buttons while the Focus menu is active. Make sure the number from Focus End Point is changing as you focus. Fine-tune the position with scrollwheel.


5. Go to Rack Focus and press SET or PLAY to start rack focus.


6. To return to the starting point, run rack focus again.
04-10-2015, 05:33 PM   #21
Site Supporter
dakight's Avatar

Join Date: Sep 2014
Location: Phoenix, AZ
Photos: Albums
Posts: 1,178
QuoteOriginally posted by jonby Quote
...
Yes I have done some manual focus stacking myself and it can be fairly-to-very tedious, depending on how many shots you need to take (which you won't know without experimenting). It's a lot easier with an old manual lens with a decent focus throw and smooth action, but difficult to impossible with a lot of AF lenses, which is one reason why this feature is needed. Automated focus stacking would certainly be a useful function, though actually my main desire is for a system which allows me to guarantee getting optimum focus in a given situation. Two different uses, similar methods.
...

Yeah, I understand, but the first step to stacking is to obtain the bracketed images, whether it's for HDR, DOF, or just to improve the chances of hitting the target exposure or focus. The difference is entirely in how the images are handled in Post Processing; up to that point it's all the same. We take exposure bracketing for granted but automated focus bracketing is virtually non-existent.
03-05-2016, 10:58 AM - 2 Likes   #22
Junior Member
DavidDwight's Avatar

Join Date: May 2014
Location: Indianapolis
Photos: Gallery | Albums
Posts: 44
but wouldn't micro-adjustment work?

QuoteOriginally posted by stevebrot Quote
You are correct. The idea that the body knows exactly how the lens is doing its work is one of the most common misunderstandings of users on this site who are seeking to tweak their AF systems.


Steve
while it might not be like commanding a stepper motor... " focus, shoot, back up 30 impulses, shoot, go forward 60 impulses, shoot, ..." why wouldn't using the micro adjustment bias feature be feasible: "focus, shoot, adjust micro focus bias + 2 steps, re-focus, shoot, adjust micro focus bias -4 steps, shoot, ..." This may not be great for handheld

The focus adjustment bias feature is built into the camera already... let's take more advantage of it

AND while you are at it here is what I want from the firmware in the micro-focus adjustment/calibration menu: <Sample Focus>
here is how it would work:
I get the camera set up on a tripod and pointed it at calibration target, ...
I go into the Micro Focus calibration menu and then select sample focus then hit the shutter button
1 Camera sets Focus adjustment to +10
2 Camera moves Lens to infinite focus
3 Camera focuses on target
4 Camera puts up the mirror for two seconds and takes exposure
5 Camera moves Lens to close focus
6 Camera focuses on target
7 Camera puts up the mirror for two seconds and takes exposure
8 Camera decrements focus adjustment 1
9 camera repeats steps 2 through 8 until focus adjustment is -10
The result is 42 exposures
It may take 2 minutes or so to run through the protocol

I'm assuming you could also make the camera write something into the EXIF Data to let you know what the settings were

Take set of 42 exposures back to your computer... you find the best one... and that is the adjustment to you should use.

If the software was really fancy it would make sure the aperture was wide open or Close before being allowed to execute. It might also demand low ISO, high state of charge on the battery, centre focus point, high shutter speed, turn off shake reduction etc.
03-05-2016, 12:44 PM   #23
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 10,828
QuoteOriginally posted by DavidDwight Quote
The focus adjustment bias feature is built into the camera already... let's take more advantage of it
Agreed. That's a very handy capability that could do lots more. Focus bracketing for macro (shoot 5 AF bracketed shots), AF adjust automation as per your example, or help automate AF adjust in some other way (eg Nikon D5/D500 style “Auto AF Fine Tune” using LiveView + AF adjust) etc.

03-05-2016, 07:34 PM   #24
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,424
QuoteOriginally posted by DavidDwight Quote
The focus adjustment bias feature is built into the camera already... let's take more advantage of it
The AF fine adjust does not work that way, but if it did what you describe might work.


Steve
03-05-2016, 09:35 PM   #25
Junior Member
DavidDwight's Avatar

Join Date: May 2014
Location: Indianapolis
Photos: Gallery | Albums
Posts: 44
QuoteOriginally posted by stevebrot Quote
The AF fine adjust does not work that way, but if it did what you describe might work.


Steve
how does the bias work? If a lens was good at '0' wouldn't setting the AF fine adjust to -10, -5, 0, +5, and +10 give you a "bracketed" set of 5 focal planes?
03-07-2016, 05:39 AM   #26
Site Supporter
dakight's Avatar

Join Date: Sep 2014
Location: Phoenix, AZ
Photos: Albums
Posts: 1,178
The Olympus OM-D has a focus bracketing mode. I don't know the details of how it works but it is built in to the latest firmware.
03-07-2016, 06:01 AM   #27
Senior Moderator
Loyal Site Supporter
Nass's Avatar

Join Date: Aug 2009
Location: The British Isles
Photos: Gallery
Posts: 2,251
QuoteOriginally posted by dakight Quote
The Olympus OM-D has a focus bracketing mode. I don't know the details of how it works but it is built in to the latest firmware.
yes, it's supposed to be pretty good. Magic Lantern (os Canon firmware) also has focus stepping as one of the functions.
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!
auto, button, camera, depth, dslr, field, focus, photography
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Landscape Uphill Ghost Bracketed HDR clevedonclarks Photo Critique 3 09-25-2012 01:40 PM
Help with bracketed exposures RockvilleBob Troubleshooting and Beginner Help 11 07-24-2012 03:31 AM
Bracketed shot Ryan83 Pentax K-r 8 07-06-2011 03:59 PM
Dlisplay All Bracketed Exposures-CS4 Bick Digital Processing, Software, and Printing 7 10-24-2010 09:01 AM
Bracketed Exposures - K10D vs K5 Mark Morb Pentax K-5 10 09-29-2010 07:14 PM



All times are GMT -7. The time now is 07:22 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