Double Vision using CPL??

[Photo Gib]

While I was on vacation over the weekend I used a CPL on several of my shots to enhance the sky and water. I didn't notice any problems with my 24-70 2.8L nor my 16-35 2.8L (other than slight vignetting). However, I got a double-vision effect when I used the CPL with my 300 4.0L, and a little bit with my 70-200 2.8IS as well. It's not focus or regular distortion caused by putting a cheap filter's glass in front, but an actual double image.

1) Does anyone know why this may be happening and is this expected with the use CPL's with long lenses?

2) Could this be happening to a lesser degree with my regular and ultra-wide telephotos but I'm just not noticing because of scale?

Any advice would be appreciated. :)

Gib

Here is an example of the 300 4.0L with CPL. Without the CPL the boat is tack-sharp. The effect was strong enough that I noticed the problem through the eyepiece and I zoomed in on the image using the LCD after the shot just to make sure I didn't need new glasses. LOL

[In2Photos]

Looks like camera shake. EXIF shows 1/50 f/8. For a 300mm lens I hope you used a tripod.

EDIT: Does your 300 have IS as well? Maybe the IS is affected by the CPL.

[Photo Gib]

Looks like camera shake. EXIF shows 1/50 f/8. For a 300mm lens I hope you used a tripod.

Yep, on a tripod and I took the picture 5 times at different settings and got the same result. As soon as I took the CPL off I had no issues.

EDIT - yes, IS too. I'll try a few shots this afternoon w/ and w/out the IS to see if that makes a difference.

However, I did have the problem with my 70-200 2.8 IS as well. I find this really weird.

[In2Photos]

EDIT: Does your 300 have IS as well? Maybe the IS is affected by the CPL.

I added this as well. Maybe someone else with some more experience can jump in and help.

[Wilt]

By any chance, is this a Tiffen filter?

[Photo Gib]

By any chance, is this a Tiffen filter?

It's a Sunpak. I'm planning on buying a Hoya or B/W this week but I wanted to find out what this issue is all about first.

[Wilt]

I had a polarizing filter and was comparing it to a CPL to visualize the difference in the effect. Turning it in my hand, I suddenly could see the thing was acting like a prism... That got thrown out promptly! I suspect you have a flawed filter as well.

[Double Negative]

Go buy a decent CPL...

Secondly, is it a linear or a circular polarizer? If it's the former, see step one.

[Tapeman]

Lools like the CPL to me. Spend about $150. for a 77 mm that will fit many of your lenses. Problem solved.

[Photo Gib]

I'm ordering a new one tomorrow. This is more confusing than ordering a new lens! LOL This is the one I plan on ordering: http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=155155&is=REG&addedTroughType=categoryNavigation

Because of the expense of a decent filter I'm thinking about using step-up rings for my 72mm and 67mm lenses instead of buying additional filters. Does anyone see an issue with that? It will obviously increase the distane between the top of the lens and the filter... I don't know if that should cause any problems???

Thanks! Y'all are helpful! :)

EDIT: is there any reason I should consider a linear over a CPL?

[angryhampster]

Hate to get off track..but isn't 1/50 a bit slow for 300mm, even with IS on? I've never used IS, so i'm not completely sure on how it works, but that just seems insanely slow for that focal length.

[Wilt]

Is there a reason you want the ultrathin version of this filter? The thin version has the S-HMC coating which is superior to the HMC coating on the ultrathin, and the filter costs no more than what your link points to.

[SkipD]

Hate to get off track..but isn't 1/50 a bit slow for 300mm, even with IS on? I've never used IS, so i'm not completely sure on how it works, but that just seems insanely slow for that focal length.That isn't getting off track. My first impression when I saw the image posted was camera/lens movement. I didn't have time to check the exif data, but you're right. Unless that camera/lens was on a very sturdy tripod, the primary problem is almost definitely camera/lens movement during the exposure.

Putting the CP filter on the lens reduced the light available to the sensor by about two stops. That, because the OP was using aperture priority, caused the camera to slow down the shutter speed from 1/200 or so to the 1/50th second - too slow for the conditions.

[Double Negative]

I'm ordering a new one tomorrow. This is more confusing than ordering a new lens! LOL This is the one I plan on ordering: http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=155155&is=REG&addedTroughType=categoryNavigation

Because of the expense of a decent filter I'm thinking about using step-up rings for my 72mm and 67mm lenses instead of buying additional filters. Does anyone see an issue with that? It will obviously increase the distane between the top of the lens and the filter... I don't know if that should cause any problems???

Thanks! Y'all are helpful! :)

EDIT: is there any reason I should consider a linear over a CPL?

For that kind of money you might as well get a Heliopan or B+W, which are even better. With the Hoya filters, you want to stick with their "Pro" line which has better multicoating.

Using step-down rings is a totally viable solution. I have a Heliopan 77mm CPL... Which I can't use on my 35mm f/1.4L lens since it has a 72mm filter thread. There was no way I was going to spring for another CPL just for this lens - and thus got a 77-72mm step-down ring. That having been said, you'll need to pay attention to the hoods of the various lenses. For example, you might not be able to slip the hood over the filter/ring combo and will have to attach the hood first, then the filter.

You should absolutely avoid linear filters. They don't work with autofocus cameras.

[Photo Gib]

Hate to get off track..but isn't 1/50 a bit slow for 300mm, even with IS on? I've never used IS, so i'm not completely sure on how it works, but that just seems insanely slow for that focal length.

Skip and AngryHampster: Yep, I was on a sturdy carbon fiber Gitzo tripod. I took 5 shots using varying settings but I only grabbed this one from the bunch. The others were taken at higher ISO and shutter speeds up to 1/320th and all produced the same result.

AngryHampster - you aren't by any chance a Python fan? Great name! :D


Is there a reason you want the ultrathin version of this filter? The thin version has the S-HMC coating which is superior to the HMC coating on the ultrathin, and the filter costs no more than what your link points to.

Thanks for the tip. I was thinking that the ultra-thin would help with vignetting on the ultra-wide angle lense but if the version you listed above is superior in quality I'll go that route instead.

[Double Negative]

Thanks for the tip. I was thinking that the ultra-thin would help with vignetting on the ultra-wide angle lense but if the version you listed above is superior in quality I'll go that route instead.

To be honest, I haven't really looked into Hoya filters that much, Pro or not. But on Heliopan filters, you can get SH-PMC in regular and slim. Also, on both versions there are filter threads on the front... So not only can you stack another filter (best avoided if possible) but you can *still use your lens cap*

Be careful you don't end up with a filter without front threads!

I have the slim filters on all my lenses. The caps still fit, but not well - the "Tamron style" work better for me. With the crop bodies, to be honest, I don't think I needed them - but I wanted to be ready for FF down the road.

[angryhampster]

AngryHampster - you aren't by any chance a Python fan? Great name! :D



Nope. I have no clue what you're talking about. :lol:


Since the shutter speed issue has been ruled out though, I'm guessing it's just an issue of the filter itself. Switching to a better brand should solve the problem.