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-   -   How do you use Filters? (https://www.dvinfo.net/forum/open-dv-discussion/33466-how-do-you-use-filters.html)

Todd Siechen October 14th, 2004 07:07 PM

How do you use Filters?
 
This is for those of you who do not use Matte boxes - how do you use filters with add-on lenses that don't have front threads? And without putting the filter between the camera and the lens. Is there a clamp on adapter with front threads for this?

Thanx for any help

Nick Jushchyshyn October 14th, 2004 09:51 PM

What camera do you have that doesn't have threads?
I've just looked a even my oldest personal camcorder (a Canon Hi8) and it has threads (as does my GL2 and ZR25).
I didn't realize that anyone made a camera without front threads.

Peter TK Lee October 14th, 2004 10:03 PM

I think Todd was referring to an add-on lens rather than the lens the camera came with. Possibly a Canon camera anyway?

Peter

Todd Siechen October 14th, 2004 10:28 PM

Yes thank you Peter - I need to be able to use a polarizer with the Century Optics .55x and .65x which don't have front threads on my Canon GL2 - of course I can use the polarizer with the camera only built-on 58mm threads but this isnt the problem. I have been considering a matte box, but most of them won't work with the wider angle lenses due to vignetting. I thought about a Cavision with the bellows but apparently the filter holders arent very solid. If I get a wide matte box then it sorta loses its usefulness for longer narrower shots.

I did purchase one of the Cinetactics matte boxes and its nice and I may be able to use the big 4X4 filters with it with some clips of some sort, but the velcro system is a poor application for using large heavy 4x4 filters and get kind of hard to use with a polarizer and the need to rotate it.

There doesnt seem to be a solution I can find.

Bill Ball October 15th, 2004 07:02 AM

Have you looked at Century's DS-FA82 sunshade?

http://tinyurl.com/58yg4


It clamps on and takes a 82mm filter.

I am going to pick up one of their 16:9 adapters for my Gl-2 and want to use a polarizer also. So I am going to send an e-mail off to them to make sure the DS-FA82 doesnt vignette. Will report back with the results

Marco Leavitt October 15th, 2004 10:19 AM

I have a Century Optics sunshade that looks exactly like the one you linked to, except mine takes series 9 drop in filters. I use it with their 16:9 adapter have no trouble with vignetting at all, even at full wide. It provides a surprising amount of flare protection too.

Pete Wilie January 18th, 2005 01:28 AM

Marco,

Are you using the Century sunshade with a GL2 and the Canon WD-58 wide angle adapter?


Bill,

Did you ever buy the Century DS-FA82 sunshade? If so, how does it work with your GL2 with the WD-58 wide angle adapter?

Marco Leavitt January 18th, 2005 07:30 AM

I actually have a GL1. I have tried it with the WD-58 and it does work. I've never used it for anything though, as I use the 16:9 adapter for pretty much everything.

Bill Ball January 18th, 2005 03:39 PM

Thanks for reminding me that I was going to report back.

I bought the Century 16:9 adpater and also the DS-FA82 sunshade and some 82mm round filters to go with it.

So far I have had mixed results with the 16:9 adapter. I knew I would lose the top half of the zoom range to soft focus. I did not know that I would experience vignetting at the other end. I bough the screw mount for my Gl-2 and experienced significant vignetting at full wide. It did not show up in the viewfinder but it was in the overscan area once I previewed the full frame image on my NLE. To their credit Century took the lens back and checked it over to make sure its wasnt faulty. They also exchanged it for no charge for a bayonet mount which still has a bit of vignetting in the overscan area but much less than the screw mount version. By the time I zoom in a bit to eliminate any barrel distortion the vignetting is gone, so I can live with it.

I just tried a quick and dirty shoot of a resolution chart with the 16:9 adapter, against the plain camera in electronic 16:9 and with the wide angle adapter in electronic 16:9. The advantages of the 16:9 adapter over the other two was obvious from the still frames, especially in vertical resolution.

To the question of the hour: using the DS-FA82 sunshade with the Canon wide angle lens. The Sunshade is a simple, light but sturdy affair with threads for a 82mm circular filter and a clamp on mount for the camera. The camera mount also has an insert for various sized lenses.

The sunshade mounts on the 16:9 adapter and takes a filter with no additional vignetting.

The sunsade mounts on the WD-58 (with the insert removed) very nicely with no vignetting in the full frame at full wide, even with one full height filter screwed in. I tried stacking in another filter on top of the first (both full height) and it started to vignette.

So for $150, the DS-FA82 is a very good add on for the 16:9 or the WD-58. The shade and filters are a LOT cheaper than matt boxes & square filters.

Given it's flat, rectangular sides, it would be a snap to tape on a piece of cardboard on the sunshade if you needed a bigger french flag sort of thing. With just the sunshade on either extra lens it still fits in my Kata 102 case fully assembled with battery, which is real cool.

Unless you really need two filters at once, or want to really look cool with the current fad. I would recommend the DS-FA82 over the much more expensive matt boxes.

Bill

Marco Leavitt January 18th, 2005 04:16 PM

Bill,
I'm shocked that you have any vignetting. I have none. Ever. I'm pretty sure that the GL1 and GL2 have essentially the same lens, so I don't know how to explain this. Since Century agreed to examine the lens, and then exchange it, I think it's safe to assume that they don't think it should be vignetting either. Are you seeing dark edges in all four corners, or just two? I have to wonder if you have the adapter aligned properly. Also, you are talking about vignetting without the sunshade and filters, right?

Bill Ball January 18th, 2005 04:38 PM

The guy at Century seem surprised also--they apparently haven't seen this either before now. That's why he asked me to send the first lens for him to check out. Since I am getting at least a bit with both lenses I have tried, I assume it's my camera.

I did read once about variations in the alignment between the optical path and the CCD on cameras within factory spec.--not enough to show up with the built in lens but becoming apparent with add on lenses. I guess I got one of those. I was pretty bummed at first. But the bayonet mount lens almost eliminates the problem and as long as I rember to tap the zoom a tiny bit from full wide I will be OK. With the bayonet mount lens it is just a tiny amount in one corner. Just one more thing to remember in the field :(.

I fully tested it with the lenses mounted correctly. Century was able to duplicate the problem also with their GL-1 so I guess instead of me being unlucky exception maybe you are just the lucky exception that you have never encoutered it. It does not show up in the camera viewfinder or LCD, or any monitor that is not in underscand for that matter. It only shows up in the full frame when displayed on the computer.

Now that I think about it, it's strange that Century claims they have never had this problem before yet they were able to duplicate my problem with both lenses on their GL-1.

Oh well I'm ready to stop obsessing about it and move on to actually shooting with it.


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