Thanks Ken.
With CPL exposures ranged from 1/400 to 1/2000
Without CPL exposures were 1/2000
I would have thought that it would be the actual exposure, ie the actual time the shutter was open, that allow an image to blur as the camera moves. I did not think that the effective shutter speed could cause that.
Last edited by joebranko; 11th March 2017 at 01:53 AM.
Hi Joe,
Others have commented on your EXIF data - I can't seem to see that using Chrome on my Mac. So if my next comment seems idiotic it is only because I can't access the EXIF data.
Is it possible that because the CPL is causing less light to reach the sensor, as a result your camera is shooting at a lower shutter speed in those situations (you are shooting in aperture priority) because you have selected a maximum ISO above which you don't want to shoot? You indicated your shots were taken between 1/400 and 1/2000. Is it possible that the blurry shots were at 1/400 at FL 250mm?
Have a great one.
Michael
Joe,
Was the 'blur' specific to parts of the image that could possibly be moving or parts of the image that would have definitely been static.
I think there are too many variables and unknowns at present and your next step is to undertake controlled tests with the camera on a tripod with a static subject.
In the 2nd shot of the swan the floating object appears to be in sharper focus than the swan. Exif indicates this image was shot at f/5.6 and 250mm. Could this be a depth of field problem? How far away was the swan? Did you focus and recompose?
Joe - what focus mode are you using to take these shots? I find that anything other than single point focus when using a long focal length can end up fooling the autofocus system and it selects the incorrect focus point. While this is not always the case, I find it does happen a lot.
The other thing I find interesting is that the only image that appears to be properly exposed is the first shot taken without the polarizer. The remaining shots appear to be a lot darker, and that should not be the case as the camera's metering system should be compensating. The only time I have seen this effect is when a linear polarizer, rather than a CPol was used.
I want to ask some thing to you Mr grumpy may I
Sent from my Micromax A311 using Tapatalk
Maybe it's an issue or maybe not. Due to the use of your filter and the s-program the camera went to the maximum aperture, 5.6.
Maybe compare images at the max. focal length and a max aperture.
I'm not sure, but is that floating object in the blurred picture sharp or not?
George
#2 looks to me like you missed focus on the swan - the buoy seems to be in reasonable focus so I suspect the camera focused on the water rather than the swan.
I can't see the Exif data so I don't know what focus modes and area you were using. Can you select just a single point? Even with a single point I find it very easy to miss my intended target at the long end of a zoom. The camera will take the shot because it has indeed found focus - just not quite where you intended - and with the shallow DOF of a long lens.....
If you have the option to select AF + MF I find it invaluable; when the camera finds focus I tweak the MF ring (and use a 3X magnification of the target) to verify I've really got focus on what I want.
Even the version 1 is capable of images taken at 250mm that appear sharp and well focused, particularly at this low resolution.
I too suspect motion blur. Note the the example you posted of a clear shot without a CPL was taken at 1/2000. If the problem were focus, there would be a plane either in front of or behind the subject that is sharply in focus. Not the case in your second shot.
I cannot give any explanation for Jobranko's blurring in his bird image, but I understand rpcrowe's problem better than he does, because I'm older; he said," too old to be climbing on wet rocks with the surf coming in." That's only half of it. Doing anything at all on wet rocks under a pier with a beautiful girl is likely to cause very shaky results, and especially so at seventy-six.
Having looked through the backwards and forwards of the discussion so for, from what I can understand (correct me if I'm wrong) that this issue occurs only when you have a CPL filter involved. Is it always the same CPL filter?
If that is so, logic suggests to me that you take a set of test shots of the same object,using the same settings and under the same conditions, with and without the CPL, with and without a tripod. Vary your SS and F-values as you will but match them in each case.
A few questions about the CPL. What make and type (EG Hoya Pro Multi Coated), how old is it, what condition is it in? Is it absolutely pristinely clean? Is there another CPL you can put on the camera in its place, or can you put the filter on another, known good, lens?
Last edited by Tronhard; 11th March 2017 at 06:53 PM.
Manfred mentioned something worth commenting on. Years ago, I shot with a Canon FD SLR camera. The exposure and focusing of that camera was not impacted by the use of a linear polarizing filter. I later purchased a Pentax ME and both the focus and the exposure were off when I used my polarizer.
I asked a Tiffen representative about this problem and he said that it resulted from using a linear polarizer and gave me a Circular Polarizer which took care of both focus and exposure problems.
I occasionally see linear polarizers on sale at eBay or on craigslist so they are still out there. It might be worth checking whether your polarizer is linear or a CPL...
The fact that there is no manufacturer's name on your CPF is, to me, a bit of a red flag. Quality filters of any kind have their manufacturer's name and type proudly emblazoned on the filter. My SUSPICION therefore, is that you may have a generic filter, which could mean poor quality optics.
I would still consider doing what I suggested with regards testing if you are in any doubt, but if you really want to take that variable out of the equation I would suggest getting a name brand, glass multi-coated filter. Having spent good money for a camera and lens, it is a big risk to put a piece of cheap glass or plastic in front of it.
Everyone will have their own opinions, but I have Hoya Pro MC filters, or Kenko (I believe they are a Hoya subsidiary) for smaller dia lens they will not break the bank. If you were putting a piece of L glass behind them maybe B+W... If you still aren't sure, take your camera to the store that sells filters and ask if you can try the filer on in their shop before you buy. Shoot with and without the filter and get them to put the result up on one of their screens. If they are a good store they will be happy to do so.
Last edited by Tronhard; 12th March 2017 at 01:11 AM.