Hoya CPL defocusing photos

So, my new CPL filter came today and I have now answered my own query. I did some controlled shots with my usual test props and can confirm that it was indeed a faulty CPL filter.

Now, before I get ridiculed for not using a tripod, I am perfectly capable of hand holding at 200mm as these photos show. Processed straight from DPP with no sharpening

Don't be too quick to blame technique - sometimes it is the tools that are at fault

I hope this thread helps somebody - it has certainly helped me! The old CPL is now consigned to the bin

Again, 100% crops:

Incidentally, I took other shots with the CPL turned 1/4 and 1/2 around and the results were the same. Last lot

I don't expect to be using filters on long(er) telephoto prime lenses but out of curiosity (given my recent experiences) I tried my new CPL filter on my 300mm f4L prime lens. Even before I selected settings manually, I saw a defocused/ghosted image through the viewfinder. And then using both AF and MF, I could not achieve sharp focus on my chosen subject. This didn't bother me as I got decent images without the filter - but I was curious to find out.

Is this normal for longer focal lengths?. I guess the additional magnification offered by the lens just exaggerates the imperfections

Any thoughts/comments?

Im pretty sure it wasn't an insult to suggest that you use a tri-pod, its called controlled testing. removing a variable. But that point has been made. The other thing is ask yourself why your are using the filter in the first place. Actually the only lens I have had scratched was because it had a filter on it, which shattered while in the over head bin on a plane. When you put an extra piece of glass in front of a very expensive lease... with out a specific reason.... a cpl is used to rehape light passing through it.... stuff happens. Unless there is a very specific reason to have something reducing the light passing through your lens, just don't do it.

Lots of times a cpl is a very handy tool. Its just not supposed to be parked on the front of your lease most of the time. Glad you figured out the solution to your problem....

Thank you

The reason for using a CPL filter was to darken an otherwise weak blue sky and give it more saturation along with the red of the signal in this instance. I have used CPL filters for years and thus, am well aware of their uses. In any case, I never keep the filter on the lens all the time; on the contrary, it is more often "off" than "on" as I shoot (mainly) moving trains and don't want to sacrifice 1-2 stops of light or raise ISO more than I have to.

I have been using digital cameras ever since the 5D Mark 1 and have never, ever encountered this focus problem before - hence my initial panic and question to the forum. I was also taken aback when "pounced upon" regarding using a tripod - I have been taking photographs for over 40 years and know how steady (or not) my handheld shooting is. I initially took this as an insult as I was looking for an authoritative answer from other experienced photographers - however I got accused of being "prickly". I am not a beginner.

collectingrocks wrote in post #19096285
I have been using digital cameras ever since the 5D Mark 1 and have never, ever encountered this focus problem before - hence my initial panic and question to the forum. I was also taken aback when "pounced upon" regarding using a tripod - I have been taking photographs for over 40 years and know how steady (or not) my handheld shooting is. I initially took this as an insult as I was looking for an authoritative answer from other experienced photographers - however I got accused of being "prickly". I am not a beginner.

I am sorry that you felt 'pounced upon' as if we were rebuking you failure to use a tripod. As Croasdil made very clear, we were making suggestions to remove as many variables as possible -- so that the ONLY conclusion was a bad filter.

Wilt wrote in post #19096292
I am sorry that you felt 'pounced upon' as if we were rebuking you failure to use a tripod. As Croasdil made very clear, we were making suggestions to remove as many variables as possible -- so that the ONLY conclusion was a bad filter.

It's ok. Glad I figured it in the end

collectingrocks wrote in post #19096285
Thank you

The reason for using a CPL filter was to darken an otherwise weak blue sky and give it more saturation along with the red of the signal in this instance. I have used CPL filters for years and thus, am well aware of their uses. In any case, I never keep the filter on the lens all the time; on the contrary, it is more often "off" than "on" as I shoot (mainly) moving trains and don't want to sacrifice 1-2 stops of light or raise ISO more than I have to.

I have been using digital cameras ever since the 5D Mark 1 and have never, ever encountered this focus problem before - hence my initial panic and question to the forum. I was also taken aback when "pounced upon" regarding using a tripod - I have been taking photographs for over 40 years and know how steady (or not) my handheld shooting is. I initially took this as an insult as I was looking for an authoritative answer from other experienced photographers - however I got accused of being "prickly". I am not a beginner.

Unfortunately there are a few here who are very proud of their skills.... and it shows up in some of their post. Most of them though I have found them to be most resonable most of the time. I personally don't use CLPs much anymore as I found the only really good ones to be quit expensive. Not the sam as a good a good cpl.. digital fixes a lot of the issues.

This does highlight the import of using truly quality filters; one may question whether you got a legitimate copy of your Hoya, as part of all of this; as filters and batteries are two of the most notorious counterfeit targets out there. It is also possible that your particular copy of the *lens* is not particularly tolerant of the additional glass of the CPL.

I have a very high quality and well used B+ Kassemann that I've enjoyed for years; it performs wonderfully on my 24-105, my 10-22 EFS and my 16-35L f/4. It performs modestly well on my 70-200L 2.8, with only slight degradation visible if pixel peeping and looking for it. It is absolute gutter trash when paired with my 100-400 Mk 1 and I've never even attempted it with the MkII for that reason. <shrug>

Glad you've narrowed it down, though.

Snydremark wrote in post #19096514
This does highlight the import of using truly quality filters; one may question whether you got a legitimate copy of your Hoya, as part of all of this; as filters and batteries are two of the most notorious counterfeit targets out there. It is also possible that your particular copy of the *lens* is not particularly tolerant of the additional glass of the CPL.

I have a very high quality and well used B+ Kassemann that I've enjoyed for years; it performs wonderfully on my 24-105, my 10-22 EFS and my 16-35L f/4. It performs modestly well on my 70-200L 2.8, with only slight degradation visible if pixel peeping and looking for it. It is absolute gutter trash when paired with my 100-400 Mk 1 and I've never even attempted it with the MkII for that reason. <shrug>

Glad you've narrowed it down, though.

I own quite a few "L" glass lenses and camera bodies, and have always bought Hoya "Pro-type" filters (£100 on average). Never had a problem before as I say and thus, never had the need to change brand. I have therefore taught myself a valuable lesson. And I would never dream of buying 3rd party batteries - always the specific manufacturer, e.g. Canon.

But yes my 70-200mm lens has been "tolerant" of Hoya previously until I was in a rush one day and dropped the CPL which rolled into the river. The replacement (which I did not use for a long time) turned out to not "like" the lens. And I did not have any other 67mm diameter lenses to try it on - hence buying another one.

At least I was lucky to return to site and retake the pictures...