Filters, Polarizers & Hoods

[hamm3r]

OK, I finished my homework of scouring through all of the posts here, but I still have some questions.

1. I have decided I would like to buy a circular polarizer, mainly because at a yearly balloon festival I went to, the ballons came out underexposed against the sky. I understand that polarizers work most at 90 degrees to the sun, but on this particular day it was overcast.
Q1: I understand that polarizers have minimal but maybe some affect on a cloudy day. With this understanding, would a polarizer have been my answer on the cloudy day or is there another approach?

Q2: Silly, but there are so many lens hood choices. Having zero experience with them, what do I look for? (Like what do all of the numbers mean?? How do I choose?) Can any recommend a very basic but quality lens hood?

3. My understanding is that Hoya & Tiffen make great filters/polarizers but that B+W is the best. I have decided I may want to go with B+W UV Haze 10 Multicoated and the B+W Circular Polarizer.
Q3a: How do I know what all of the numbers mean (37, 39, 43, 46, 48, etc) for example, on this page?
http://www.canogacamera.com/e/env/00012rAwzviqwX8iqU0P9q8/schneider/bw_uv_warming/bw_uvmain.html?link=bw_uv010.html
Q3b: How do I know a filter will fit on my lens? (50mm/1.4 and the 300d Kit lens)
Q3c: Why would I want or need to buy the slim version?

[JonathanS]

Well, I can tell you what the numbers mean, they are the diameter of the lens thread, your lens should have its diameter somewhere on it and you must get a filter that matches that number or it wont fit. There are step-up and step-down rings that can let you use different size filters but, why not just get the right size. As for the lens hood I use a rubber hood that can be folded back without taking it off, I have no real technical reason for using that hood only that it helps protect the lens and the whole stray light thing as well as it can be easily "removed" (folded back) when you don't need it.

By the way the 300D kit lens is 58mm (same one I use).

[lancea]

A1: on a cloudy day the light will be scattered in all directions so the polariser will act as no more than a neutral density filter. It can however still reduce reflections so has a use, but it probably won't help your balloons. You just have to watch the histogram to avoid blowing out the sky, and shooting RAW would give you a better chance of later recovering sky-detail if it is blown a little.

Q3c: a slim filter is only necessary on a wide angle lens. It won't be necessary at 18mm though as due to the crop-factor of your camera's sensor it is effectively only a moderate wide angle. The other time it may be necessary (even at 18mm) is if you are stacking filters, e.g. a polariser on top of a UV. If you don't use the thin variety, you'll likely get shadowing of the edges of your photos.

[CoolToolGuy]

Q1: Most likely, your shots were underexposed because the large amount of sky in your image was brighter than the balloon(s), and the meter averaged it all out. The polarizer would not have cured that problem.

Your Drebel does not have spot metering, but if it did you could meter on the balloons, hold it (exposure lock), recompose, and then take it. As it is, your best bet would either be to zoom in to get just the balloon, or use AE bracketing, or just guess. If you do this a lot you will come to know what a good amount of exposure compensation is.

Q2: Canon makes specific hoods for each of their lenses. They are, however, made for a full 24x36 frame. The kit lens, however, is an EF-S lens (digital only), and the hood for it is made for digital. That said, the hood for the 18-55 is pretty small, and will not block out much sun. I would skip it for the kit lens. Aftermarket hoods can do the job, but you should do some tests as soon as you get one to make sure there is no vignetting from it.

If you are using a polarizer, it will block out most of the stray light, so a hood may be unnecessary. In addition it becomes difficult to rotate the polarizer with a hood attached. I have the hood as well as a polarizer for every lens, but I don't usually use them at the same time.

Q3c: I will differ with lancea regarding the filter. For EF lenses that are made for full frame, you can get away with stacking 2 or 3 filters before vignetting occurs. For your 50mm and tele that will probably be true. But the kit lens was designed for digital, and Canon usually only provides for one filter. If you get thin filters you may be able to stack a UV and a C-POL. Beware, though, that most of the thin filters do not have a front filter thread, so you cannot stack and you cannot use the snap-on lens cap. Hoya Pro-1 filters are the thinnest available with a front thread, but they are a little pricey.

Hope this helps.

Have Fun,

[shiato storm]

mainly because at a yearly balloon festival I went to, the ballons came out underexposed against the sky.should have got at night...if you're talking about the same one I'm thinking of...

[lancea]

But the kit lens was designed for digital, and Canon usually only provides for one filter.
Not sure what you mean by Canon only providing for one filter. As you say, this is purely a function of the filter. If you're going to the expense of a thin filter, it makes sense to me to get one with a front thread (if only to fit the standard cap! :) ). Also unsure why "designed for digital" would make a difference and would be interested in why you say that.

[hamm3r]

Thanks for the responses so far!

Your Drebel does not have spot metering, but if it did you could meter on the balloons, hold it (exposure lock), recompose, and then take it. As it is, your best bet would either be to zoom in to get just the balloon, or use AE bracketing, or just guess. If you do this a lot you will come to know what a good amount of exposure compensation is.

Question: Do you think it would work to zoom in on the balloon, read the camera settings, then zoom out, switch to full manual and use the settings that I had read?

[CoolToolGuy]

Thanks for the responses so far!

Your Drebel does not have spot metering, but if it did you could meter on the balloons, hold it (exposure lock), recompose, and then take it. As it is, your best bet would either be to zoom in to get just the balloon, or use AE bracketing, or just guess. If you do this a lot you will come to know what a good amount of exposure compensation is.

Question: Do you think it would work to zoom in on the balloon, read the camera settings, then zoom out, switch to full manual and use the settings that I had read?

Yes, that would work.

Have Fun,

[CoolToolGuy]

Not sure what you mean by Canon only providing for one filter. As you say, this is purely a function of the filter. If you're going to the expense of a thin filter, it makes sense to me to get one with a front thread (if only to fit the standard cap! :) ). Also unsure why "designed for digital" would make a difference and would be interested in why you say that.

In the specs for most Canon lenses it will say that only one filter should be used. The filter ring acts as a hood, and if you put on too many filters, vignetting at the corners will occur. EF lenses are made for the angle of view of the 24x36 frame, so there is room for more than one filter before vignetting on the APS-sized frame of the 1.6 bodies. However, the EF-S lenses are designed for the 1.6 cameras, and the filter size is part of that design. I have seen this on my EF-S 17-85, where I cannot stack a normal UV and a polarizer. I got the Hoya Pro-1 UV filter, but I still get vignetting at the wide end when I add a polarizer. I want to try a Pro-1 polarizer, but they are not cheap, so that experiment will have to wait.

Hope this helps.

Have Fun,

[hamm3r]

Thanks again!