Search results for 'back focus' - page 702
16-50 problem ?
When you do the adjustment, the figure you alter is in tens of microns. I took this to be moving the sensor forwards or backwards by this tiny, but obviously significant, amount. Thanks for that Dan! I knew I was moving the sensor back-and-forth by incredibly small amounts but I couldn't figure ou...
Posted by hefty1 on 17/03/2008 - 16:55
16-50 problem ?
Thanks for that Dan! I knew I was moving the sensor back-and-forth by incredibly small amounts but I couldn't figure out what the units were - now I know. :D That's okay, although I said that, and can't remember where I knew it from. Does it say it on the adjustment screen? Anyway, when I said ...
Posted by Daniel Bridge on 17/03/2008 - 17:52
16-50 problem ?
Don't read too much into the first example, at really wide apertures then lighting does play a role and tungsten seems to exaggerate any problems. The "proper" tests I did before and during adjustment were done under natural light at exactly 45 degrees and the back focus - while still clea...
Posted by hefty1 on 17/03/2008 - 18:31
16-50 problem ?
Hello. I have just ordered the 16-50 2,8 lens. I didn't know about QC issues and FF/BF. I am really concerned about firmware fix because I've noticed that this problems occur widespreadely. So before i put my hands over my new lens I'm afraid I will have those issues too and I'm posting some quest...
Posted by taiabati on 19/03/2008 - 15:27
16-50 problem ?
First of all, download the focus test chart from and follow the instructions to find out if your camera actually has a FF/BF issue (not all do). If it does have a problem then install the hacked version of firmware 1.10 over the top of your version 1.30 ( ). Now install the real 1.10 over t...
Posted by hefty1 on 20/03/2008 - 01:05
16-50 problem ?
thanks for the explanation and How-to, I'm going to try this! I never have been able to convince myself whether I just suck or my K10D has a slight back focus issue, this should prove it.
Posted by Mongoose on 20/03/2008 - 10:19
16-50 problem ?
Thank You hefty1! After some testing it seems that I have Back Focud issues. I will try the trick and let you know. One thing still discourages me: is the problem a lens/camera combination issue or is the sensor "out of focus"? I mean, if i adjust the focus to have a sharp DA* 16-50, ...
Posted by taiabati on 28/03/2008 - 10:51
16-50 problem ?
I can only speak from my own experience and I found that my K10D was back focussing with ALL my lenses, now it has been adjusted all my lenses focus perfectly. The problem will always appear more pronounced with fast lenses as they have a much narrower depth-of-field, this doesn't mean that your sl...
Posted by hefty1 on 28/03/2008 - 11:15
50mm af 1.4mm pentax lens purple shadows
This does sound like a white balance issue, however, digital noise can look a little purple in dark areas. Take a look at what ISO you are shooting at to rule this out I would suggest using ISO 200, 400 at most. I have a manual focus 50mm 1.4 and sometimes when the lens is wide open i.e. at F1.4...
Posted by beakynet on 12/03/2008 - 13:56
50mm af 1.4mm pentax lens purple shadows
I would say (everyone's got their own opinion :wink: ) that this is due to 'Longitudinal Chromatic Aberrations', where out of focus areas in front and behind the subject show magenta or green hues. It's more pronounced at larger apertures - check your pics to see if the areas that look purply ar...
Posted by Daniel Bridge on 12/03/2008 - 18:48
50mm af 1.4mm pentax lens purple shadows
Thanks to all for the replies so far. Unfortunately I can't upload an image so the best I can do is give the following info from the first image I noticed this problem. Shot as high qual jpg in low light auto white balance, 1/20 shutter speed, 1.4 aperture, iso 100. Indoor - no artifical l...
Posted by kiwao on 13/03/2008 - 03:39
50mm af 1.4mm pentax lens purple shadows
I would say (everyone's got their own opinion :wink: ) that this is due to 'Longitudinal Chromatic Aberrations', where out of focus areas in front and behind the subject show magenta or green hues. It's more pronounced at larger apertures - check your pics to see if the areas that look purply ar...
Posted by Daniel Bridge on 14/03/2008 - 16:31
I'm in love
I wouldn't expect great things from a converter on the Bigma (The common name for the Sigma 50-500mm). I've tried a variety of them and they're useful if you cannot get a shot any other way. One of the biggest problems is the light when extended to 500mm and the ability of the camera to auto-focus a...
Posted by chirpy on 14/03/2008 - 21:09
Performance Zoom Lens?
Gary this new Sigma has my attention at the moment. Not seen any reviews on it yet but would be surprised if its not up too scratch :?: This looks like the only cost effective f/2.8 option we have for Pentax, combined with a converter this may work well. However still some debate as it has HSM w...
Posted by Clarky on 16/03/2008 - 10:38
Performance Zoom Lens?
Gary my understanding is it will Auto focus, I believe it works with HSM and as standard auto focus. The pentax 60-250 is due out in April is it not. but that is f4 not f2.8 Thanks Clarky for the info much appreciated: I have added this lens to my list now, I will wait out on the 60-250 review...
Posted by GaryMoffat on 16/03/2008 - 10:45
Performance Zoom Lens?
Have a look at the Sigma 135-400.................. Does anyone have any experience of this lens :?: For me it would appear to be ideal, carrying on where my 50 -135 stops. I have one of these and use it for airshows. If it's bright conditions and you can stop it down to f/8 or smaller, then it...
Posted by yelvertoft on 10/04/2008 - 12:38
Performance Zoom Lens?
I have one of these and use it for airshows. If it's bright conditions and you can stop it down to f/8 or smaller, then it is a fine lens - especially for the money. If you're using it in less than ideal conditions and have to use it wide open, then at either extremity of the zoom it shows it's bu...
Posted by badbrother on 16/04/2008 - 19:40
Lenses for photographing storms
Welcome to the forum. Can I just correct one error before we start? Lens is spelled "lens", not lense, a common mistake for which I can forgive you . . . once. :D Your ideal lens will be one suitable for landscape work, anywhere in the 10 to 50mm zoom range. Additionally, in storm ...
Posted by Mannesty on 16/03/2008 - 12:05
Lenses for photographing storms
Being 100m from a storm I'd want the heaviest lens possible to stop the whole lot being blown away:shock: Good luck with your trip and post some of your photos here when you get back. Steve :wink:
Posted by promhandicam on 16/03/2008 - 19:30
Sigma EX 50mm f:1.4
Or you could buy the 50mm "A" 1.7 manual focus!....for about £35/40.....it is superb and I love mine!..................
Posted by beginner on 18/03/2008 - 19:08
