Vignetting with stacked filters

[neuroanatomist]

Rick, almost no risk of vignetting if you use a step-up ring. The main downside is that you can

[Kayaker72]

Rick,


That is essentially the system I am using. I bought several filters at 77 mm and bought two step up filters (72-77 mm for the EFS 15-85 and 67-77 mm for my EF 100 L). My experience so far is:

• I can use my lens hood on the 15-85, but you have to install it first and then screw in the filter. This is difficult, but not impossible. So,I would agree that step up rings make using hoods impractical, but I have done it a couple of times when I thought I really needed it.
• Vignetting is interesting as you have two, mostly offsetting, factors. The first is that the step up ring does move the filter further from the front of the lens (similar to stacking filters), which could increase vignetting. But the wider diameter on the filter may offset this. It is all about the angle of viewfrom the lens and whetheryour step up ring set up brings the filter into the AOV.
• No issues with the 100 mm L as it has a much more narrow AOV.

Off hand, my experience is that these two factors almost perfectly offset each other. For example, I see a little mechanical vignetting with my 72 mm F-Pro CPL on my 15-85 mm lens at the widest angles (~15-20 mm on my 7Dfrom memory). I see a very similar amount of vignetting with the 77 mm F-Pro CPL mounted on the 15-85 with a 72-77 mm step up ring. If interested, I can take some photos tonight for examples.


FYI, this step up ring system is working well for me. It is a little tediousunscrewingthe UV filter and screwing in two other filters andsomeday I'll likelygraduate to a rectangular filter system, but this is good enough for now.....


But definitely invest in a few "nuns" to have around. Have a great trip.


Brant

[Kayaker72]

Also, the vignetting is much worse on the right, even in a no-filter shot. How bad is that? does it mean there's a centering or QC issue?

Yes, it means there is some decentering (misalignment of the optical elements) with your copy of the lens. A quick internet search seems to indicate it's a common problem with the lens.

Interesting. My copy of the 15-85 must be decentered a little too. I've been noticing that I get more vignetting (especially mechanical) in the topleft corner. I'll look for image quality, but I haven't noticed any yet. This is likely "if it is not broke (IQ) don't fix it" but any thoughts on fixing this?


Thanks,


Brant

[HDNitehawk]

John and Brant


Thanks. I was a little concerned about not being able to use the hood. I have used the 24mm without the hood before and it is prone to picking up stray flares.


What I went with is buying the 77mm CPL, Several ND, Several Graduated B + W screw in filters and a few Graduated Cokin P filters. I bought a 72mm - 77mm step up ring so I can use the same set up with my 35mm L.


Last year I found the 24mm to be plenty wide enough, and the 35mm would be adequate most of the time. If I get any vignetting on the 24mm I can always use the set up with the 35mm.


From John's charts I am thinking I can probably stack the CPL which has threads with a ND or Graduated Filter on the 24mm(2 total), and not have noticeable vignetting.


Rick

[HDNitehawk]

I went ahead and ordered a set of 77mm filters, ND and Graduated and a step up ring for 35L to go from 72mm to 77mm. I was concerned about not being able to put the hood on the 24mm if I went to 82mm. I also bought new XS-PRO MRC Nana Circular Polarizer.


So of course when they arrived today I had to check them.


John, I have to say they performed just as you described in your test. No surprises at all. With the 24mm I could stack two filters, with a just a so slight bit of mechanical vignetting at the edge.With three filters it was there and obvious.


With the 35mm, three stacked and no vignetting. I put the hood on first then the filters. While this seemed like a good idea, I see the mistake waiting to happen. If you do this and the filters get stuck there is no way to get leverage inside of the hood. So Looks like while the hood will fit its probably not going to be a good idea to have it on.


Thanks for the informative post.

[neuroanatomist]

Thanks for the update, Rick. I wouldn

[HDNitehawk]

An update to my last post.


The previous check I did was with the XS Pro and B+W ND Filters


I took out the 24mm L just a bit ago and stacked the new ND Graduated filters:


B+W 77mm GRAD NEUTRAL DENS GRAY #501


with a


B+W 77mm (XS-PRO/NANO-MC) KAESEMN CIRC POL


They won't stack without mechanical vignetting, the graduated is to thick. Pick speaks for itself


Of course the Neutral Density Graduated filter is much thicker than the others


[img]/resized-image.ashx/__size/550x0/__key/CommunityServer-Components-UserFiles/00-00-00-47-09/two-stacked-2.JPG[/img]


The 35mm with the adapter ring there was no vignetting at all with both filters stacked on top of an F-Pro