DA 300mm - back focusing?
Posted 23/10/2012 - 11:55 - Helpful Comment
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Looks like a tad of back focusing to me.
The last shot - the give away is that the area of tile just to the left of the feet looks sharper than the bird.
Simple adjustment in the K5 and K7 - custom menu, AF adjustment (on the last page).
You have a choice of "Apply All" (leave that as it is) and "Apply One". Set the "Apply One" to around +5 to start with and try again. If it front focuses, then lower the value. If still not correct then slightly increase the value.
If you want to start over again, just reset the value to zero and try again. The "Apply One" values are individual to each lens and are added to the "Apply All" (so if all lenses back focus you can adjust a global value and then tweak individually).
Essentially you just iterate until you get consistently good focus
Personally, I find real-world examples (like the last shot) the best for getting a decent focus adjustment.
Matt
The last shot - the give away is that the area of tile just to the left of the feet looks sharper than the bird.
Simple adjustment in the K5 and K7 - custom menu, AF adjustment (on the last page).
You have a choice of "Apply All" (leave that as it is) and "Apply One". Set the "Apply One" to around +5 to start with and try again. If it front focuses, then lower the value. If still not correct then slightly increase the value.
If you want to start over again, just reset the value to zero and try again. The "Apply One" values are individual to each lens and are added to the "Apply All" (so if all lenses back focus you can adjust a global value and then tweak individually).
Essentially you just iterate until you get consistently good focus
Personally, I find real-world examples (like the last shot) the best for getting a decent focus adjustment.
Matt
http://www.mattmatic.co.uk
(For gallery, tips and links)
(For gallery, tips and links)
Posted 23/10/2012 - 12:04 - Helpful Comment
Link
Ricehigh has a good method for adjusting the focus:
http://ricehigh.blogspot.com/2010/01/k-x-debug-mode-tutorial-af-adjustment.html
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http://ricehigh.blogspot.com/2010/01/k-x-debug-mode-tutorial-af-adjustment.html
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Half Man... Half Pentax ... Half Cucumber
Pentax K-1 + K-5 and some other stuff
Algi
Pentax K-1 + K-5 and some other stuff
Algi
Posted 23/10/2012 - 12:09
Link
Cheers Matt
I have a K-r so is that the AF fine adjustment option? Can't see an 'apply one' or apply all' option.
I have a K-r so is that the AF fine adjustment option? Can't see an 'apply one' or apply all' option.
Posted 23/10/2012 - 12:10 - Helpful Comment
Link
But you don't need the debug mode for K5 & K7 as it's already available.
For the K-r you'll need the debug mode
It's a bit more complicated - see this thread for tips
Other models will pick up a specially named file off the SD card... there's probably one for the K-r too.
Matt
For the K-r you'll need the debug mode
It's a bit more complicated - see this thread for tips
Other models will pick up a specially named file off the SD card... there's probably one for the K-r too.
Matt
http://www.mattmatic.co.uk
(For gallery, tips and links)
(For gallery, tips and links)
Posted 23/10/2012 - 12:10 - Helpful Comment
Link
Low light, a long lens,spot auto focussing and how much can you stop down your lens and keep the shutter speed up before the ISO gets too high?
I find taking plenty of shots to be patient for the good ones works when shallow depth of field in low light is the order of the day. Friday's cold northerly winds will at least bring us some light back on these otherwise short dark days.
I find taking plenty of shots to be patient for the good ones works when shallow depth of field in low light is the order of the day. Friday's cold northerly winds will at least bring us some light back on these otherwise short dark days.
Posted 23/10/2012 - 12:57 - Helpful Comment
Link
Check out your aperture used at what focal length in a table before you go messing. For example twenty feet at 5.6 and 300mm doesn't leave much latitude comapared to say F8 or F11.
Plenty of calculators on the web to check out for example
http://www.dofmaster.com/dofjs.html
Plenty of calculators on the web to check out for example
http://www.dofmaster.com/dofjs.html
Posted 23/10/2012 - 13:06
Link
Thanks all.
It's brightening up a bit so I think I'll stick it on the tripod with a fixed object later to rule out any user error!
The AF Fine adjustment in the custom menu seems to make a difference so I'll play with that first before anything else. If that works I'll just have to remember the settings for this lens. Every other lens is fine and I don't have many so shouldn't be too hard to remember.
It's brightening up a bit so I think I'll stick it on the tripod with a fixed object later to rule out any user error!
The AF Fine adjustment in the custom menu seems to make a difference so I'll play with that first before anything else. If that works I'll just have to remember the settings for this lens. Every other lens is fine and I don't have many so shouldn't be too hard to remember.
Posted 23/10/2012 - 15:44
Link
User error
I've tried it on a tripod with a fixed object and it's fine. If anything it focused slightly better at -2 so clearly wasn't the lens/camera back focusing, just me.
As Bill said, available light, aperture and shutter speed all seem to be that much more critical with a lens of this size and weight. I was basically expecting to be able to get away with the sort of shutter speeds, aperture and ISO that I might do with a smaller and lighter lens and that was foolish.
A lens this long and heavy (at least compared to everything else I have) is going to need a technique far superior to mine to use at 1/60 and have clear images......
Looking at some later attempts with this in mind it is producing some stunning image quality. The only concern for me really in deciding whether to keep it or not is the weight. I am considerably under average size, small hands/short arms, and probably going to struggle in anything less than good light. The 55-300 would probably be a better choice in that respect, but from what I have seen so far there isn't any comparison in image quality.
I've tried it on a tripod with a fixed object and it's fine. If anything it focused slightly better at -2 so clearly wasn't the lens/camera back focusing, just me.
As Bill said, available light, aperture and shutter speed all seem to be that much more critical with a lens of this size and weight. I was basically expecting to be able to get away with the sort of shutter speeds, aperture and ISO that I might do with a smaller and lighter lens and that was foolish.
A lens this long and heavy (at least compared to everything else I have) is going to need a technique far superior to mine to use at 1/60 and have clear images......
Looking at some later attempts with this in mind it is producing some stunning image quality. The only concern for me really in deciding whether to keep it or not is the weight. I am considerably under average size, small hands/short arms, and probably going to struggle in anything less than good light. The 55-300 would probably be a better choice in that respect, but from what I have seen so far there isn't any comparison in image quality.
Posted 23/10/2012 - 16:39 - Helpful Comment
Link
I think images taken at 1/60th hand held are always going to show some camera shake unless you have a very steady grip, even with SR turned on.
An old rule of thumb with film cameras was to use a shutter speed equal to or faster than the lens length in use EG: 1/300th/sec or faster for a 300mm lens. You might even have to multiply that by 1.5 to 1/450th/sec for the crop factor, then drop back up to the three stops that the SR should compensate for.
An old rule of thumb with film cameras was to use a shutter speed equal to or faster than the lens length in use EG: 1/300th/sec or faster for a 300mm lens. You might even have to multiply that by 1.5 to 1/450th/sec for the crop factor, then drop back up to the three stops that the SR should compensate for.
Peter E Smith - flickr Photostream
Posted 23/10/2012 - 16:47 - Helpful Comment
Link
milamber wrote:
A lens this long and heavy (at least compared to everything else I have) is going to need a technique far superior to mine to use at 1/60 and have clear images......
Monopod?
A lens this long and heavy (at least compared to everything else I have) is going to need a technique far superior to mine to use at 1/60 and have clear images......
Posted 23/10/2012 - 17:54
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JohnX wrote:
Possibly, but I've had one before and rarely found myself in a situation where it might be practical. Might have to get the weights and barbell out again (or just carry the lens about...)
milamber wrote:
A lens this long and heavy (at least compared to everything else I have) is going to need a technique far superior to mine to use at 1/60 and have clear images......
Monopod?A lens this long and heavy (at least compared to everything else I have) is going to need a technique far superior to mine to use at 1/60 and have clear images......
Posted 24/10/2012 - 12:50
Link
Still gloomy today, but I upped the ISO to allow a slightly smaller aperture and increased shutter speeds.
All at 640 ISO and f8. All the wildlife is in hiding so static subjects only, apart from one of my hens (which isn't quite perfect so more practice needed with moving objects). No PP other than cropping. Tried a little sharpening, but couldn't see any difference - only lens I have had where I can say that.
I think I can conclude the problem was me, not the lens.
I've never used one so would be interested in how people think these images compare to the 55-300 at 300mm?
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/028_zps30c1d2d9.jpg[/IMG]
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/016_zpse5fc6956.jpg[/IMG]
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/020_zpse22d4517.jpg[/IMG]
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/023_zps1ab6ad53.jpg[/IMG]
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/018_zps2db6c91b.jpg[/IMG]
All at 640 ISO and f8. All the wildlife is in hiding so static subjects only, apart from one of my hens (which isn't quite perfect so more practice needed with moving objects). No PP other than cropping. Tried a little sharpening, but couldn't see any difference - only lens I have had where I can say that.
I think I can conclude the problem was me, not the lens.
I've never used one so would be interested in how people think these images compare to the 55-300 at 300mm?
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/028_zps30c1d2d9.jpg[/IMG]
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/016_zpse5fc6956.jpg[/IMG]
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/020_zpse22d4517.jpg[/IMG]
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/023_zps1ab6ad53.jpg[/IMG]
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/018_zps2db6c91b.jpg[/IMG]
Posted 24/10/2012 - 14:09 - Helpful Comment
Link
milamber wrote:
I've never used one so would be interested in how people think these images compare to the 55-300 at 300mm?
300mm on the 55-300mm (all quite heavily cropped)I've never used one so would be interested in how people think these images compare to the 55-300 at 300mm?
The 300mm prime will come into it's own shooting at f4 or with a teleconverter though whereas the with the 55-300mm you have the flexibility of the zoom and price difference. It's not really a decent comparison tbh.
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863 posts
14 years
Norfolk
It's a miserable misty day so probably not the best time to test it, but it seems, to my eyes anyway, to be focusing slightly behind and to the left?
It might just be me being fussy, but I've read about back/front focusing, but never actually experienced it. I've posted a few shots below and would appreciate any advice. If the focus does need adjusting how do I test for certain and go about it?
No PP adjustment except for a crop on the 3rd picture.
Focused on the front raspberry in the first picture and just on the wagtail generally in the other two. In the second photo the wagtail is in good focus except for the insect in the beak.
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/004_zpsbd9f4319.jpg[/IMG]
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/010_zps0bd2274f.jpg[/IMG]
[IMG]http://i393.photobucket.com/albums/pp15/chriseast/013_zps9043abf4.jpg[/IMG]