polarizer

[noob873]

I was reading a lot about these and what they do so I decided I could really use one. But I would like to know the difference between them. Like I'll see one on B&H like this http://www.bhphotovideo.com/c/produc...zer_Glass.html for a little over $100, and then I searched ebay and see something like this one http://cgi.ebay.com/72mm-Circular-Po...QQcmdZViewItem

Im just curious what the difference is, obviously a lot of you will say quality, but would I notice a difference?

[tirediron]

I can't see eBay from work, but if it's a cheap polarizer on eBay (eg < $75) than I would stay away from it. It might not look bad if you look at a picture taken with it, but if you compare it to one taken with a B+H, Hoya, or even a Tiffen, you will definitely see a difference. Filters, like lenses are an area where it doesn't pay to go cheap. If you're budget concious, look around the camera stores for a good used one. As long as it's scratch-free, it'll be fine.

[Garbz]

Actually if you're budget concious I recommend ebay, just not the one you linked. CPL and UV filters especially the SHMC Hoya filters can be had there for the same price as the standard cheap Hoyas in camera stores.

[noob873]

Im not afraid to spend money as long as Im getting something nice. I've learned my lesson on buying something cheap and having to replace it with something nicer, when I could have gotten the nicer one in the first place.

But like what would be the difference between the first one I linked and something like this http://www.bhphotovideo.com/c/produc...izer_HMC_.html
Its only a $10 difference, since they're so close in price how would this one be better (if its even better)?

[noob873]

.

[Joves]

Well the cheap one on ebay is no doubt not multicoated and, the glass not as flat. The Nikons are great and, so are the Hoysa HMCs. I have the Hoyas myself and, then there is the B&Ws as well. The multicoatings kill reflections from the glass elements.

[Alfred D.]

Quote: Originally Posted by Joves

The multicoatings kill reflections from the glass elements.

That, at least, is their purpose. To what extent they succeed varies wildly. Multicoatings also introduce new layers affecting the optical properties. Casts and hues are a common phenomenon.

[Garbz]

Errr that's a new one? I have never seen multicoated glass whether it be filter, camera lens, sunglasses, or the precision optics we use for the laser amplifiers in our lab at uni that has performed worse due to multi-coating. Definitely I have never seen a colour cast.

[Helen B]

Even the best polarizing foils used for filters are not spectrally perfect, and any slight dichroic filtration caused by multicoating will be insignificant in comparison (it's usually insignificant anyway, as Garbz mentions above). There is no practical disadvantage in choosing a multicoated filter over a single coated or uncoated one, unless the coating is soft, which HMC (Hoya) and MRC (B+W Multi Resistant Coating) coatings aren't.

One of the things you pay for when you get the better polarizing filters is the quality of the polarizing foil: spectral evenness (neutrality), low absorption of the passed light and high absorption of the crossed light.

Best,
Helen

[Joves]

Quote: Originally Posted by Alfred D.

That, at least, is their purpose. To what extent they succeed varies wildly. Multicoatings also introduce new layers affecting the optical properties. Casts and hues are a common phenomenon.

Multicoatings suceed quite weel. I have used them for years on optical coatings I have ground for telescopes. The last one I did with a friend was an 8 inch tripplet. Also the coatings help with color correction in that application.

[Alfred D.]

An 8 inch tripplet isn't exactly a 35 quid, or even a 100 quid SLR filter.

[Helen B]

Quote: Originally Posted by Alfred D.

An 8 inch tripplet isn't exactly a 35 quid, or even a 100 quid SLR filter.

That doesn't stop filters from having good, effective multicoating. You seem to be the master of argumentative, misleading irrelevance.

Best,
Helen