Filter Stacking and Teleconverter usage

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Hi

I own a Canon Rebel 2000 and have different filters too. My questions are:

1. Does the UV filter cause any light loss? Can I keep it while using my camera for some night shots as it is also meant for the lens safety?

2. Users manual suggests to use only one filter at a time. Can I stack a UV filter and an 812 color warming filter to my lens? Do I have to stop down EV settings twice because I have two filters that cause doulbe light loss? What about using a circular polarizer with an 812 combination? Please tell me your suggestions.

3. How about using a 2X teleconverter to my Canon 75-300 mm EFIII lens? Any brand suggestions would help me for selecting the best.

Regards George

-- George Mathew (george_mathew2k@yahoo.com), November 20, 2001

Answers

(1) No, yes (2) Yes but it may vignette, you don't stop down "EV settings" at all, yes but it may vignette (3) Not a good idea, there isn't really a "best" only a "least worst"

-- Bob Atkins (bobatkins@hotmail.com), November 20, 2001.

To elaborate a little further:

If you're using a filter, know why. A UV filter does eliminate some light and may help to cut haze in some outdoor shooting situations. Many folks routinely leave it on their lens for protection, a good idea, especially if you're in a situation where stray fingerprints or dust, sea salt, etc. may lurk.

Every filter cuts light somewhat and introduces some degradation. That's why it's a good idea to remove the uv haze before mounting a different filter. Only stack if you need the effect each filter provides.

Make sure your polarizing filter is a circular polarizer so it doesn't interfere with autofocus.

Stacking a warming filter and a polarizer is a time-honored option for cutting glare or deepening blue in sky when the color balance may tend to the blue (mid-morning to mid-afternoon, in general.) You can get polarizers that have a warming effect built in. Stacking should work fine as well, and saves you from having to buy and lug around another filter.

A Canon tele-extender will not work with the 75-300 zoom; it physically conflicts with the lens. You could get an off-brand extender that would work, but it wouldn't be a good idea. You're already starting off with a decent, but not pro-grade, lens that at 300mm is already a slow f 5.6. A 1.4 telextender (of any brand) costs you a stop of light, so you'd have 420 f/8, meaning that you would not be able to autofocus (autofocus generally works to f 5.6 on non-pro camera bodies.) Plus, the tele-extender would introduce distortion and magnify the distortion your lens started out with, so the results would most likely be somewhat murky.

I hope that helps. Try some different things and see what works for you. Have fun!

***

-- Rod (rod.nygaard@boeing.com), November 20, 2001.


And the Ev business. Sounds like you're wondering if you have to compensate for the filter manually. You don't: the meter in the camera is looking at the light after it's been through the filter. Just set your exposure as indicated by the meter directly.

-- Rod (rod.nygaard@boeing.com), November 20, 2001.

2 points i would like to reiterate. 1) you do not need to compensate for filters on the rebel 2000 because the camera meters through the lens. it looks through the filters to determine exposure so no compensation is needed. 2) teleconverters on slow lenses don't work well. if you used a 5.6 lens with a 2x converter the resulting apeture would be f/11. try stopping down a lens you own to f/11 and try to focus manually. dark huh? if you want more length look into one of sigma's 50-500 or 170-500. they are good lenses. good luck!

-- jeff nakayama (moonduck22@hotmail.com), November 20, 2001.

oh yeah. there's also the sigma 135-400.

-- jeff nakayama (moonduck22@hotmail.com), November 20, 2001.


I have a Canon 75-300 and a Kenko 1.5X converter. They do work together and autofocus still works if there is enough light & contrast. The images are quite soft. I use it when I have to, but I certainly can't say it works well. A 2X TC would be even worse. No autofocusing or focus indication at all and the images would be very poor.

-- Jim Strutz (j.strutz@gci.net), November 21, 2001.

Teleconverters aren't worth bothering with outside of pro glass and pro TCs (like the Canons). I get excellent results from mine, but the Canon TC on its own costs more than the 75-300, so that should tell you something. Only four zoom lenses spring to mind for use with teleconverters, and, oddly enough, they're the only 4 zooms which canon sell as being teleconverter compatible, being the three 70-200 L series lenses (F2.8, F2.8 IS, F4) and the 100-400L IS.

-- Isaac Sibson (isibson@hotmail.com), November 21, 2001.

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