Want to purchase a 10 stop ND filter

lsquare wrote in post #16237906
And the Hoya doesn't have any colour cast? If so, it seems a bit hard to believe considering that both B+W and Lee's 10 Stop ND filter have a colour cast.

Did i say that it had no cast?
No, I did say that just about every review or article i saw that compared the two rated the Hoya better than that particular B+W.

oxygen45 wrote in post #16240136
Did i say that it had no cast?
No, I did say that just about every review or article i saw that compared the two rated the Hoya better than that particular B+W.

Talk about overreacting here...

Which review said the Hoya is better? I did a quick check on Google and I found mostly opinions.

Jon wrote in post #16239924
Yep. MRC for filters with a low filer factor; but as filter factor increases, the need for multicoating decreases. Possibly less if you are using a coloured filter (Wratten 12 yellow, Wratten 25 red or the like), which passes one wavelength relatively cleanly, but certainly with a ND, which blocks all wavelengths essentially equally.

So your saying the MRC version will have the same lens flair as the non-MRC version? If so, then why would they make it? That would seem kind of silly to charge 50% more for a filter with MRC and it doesn't do anything?

Take Care,
Cheers, Patrick

Jon wrote in post #16239512
Think about it. One purpose of any lens or filter coating is to reduce internal reflections that cause flare and glare. But each time light passes through a 10-stop filter it's attenuated by 10 full stops. That means that non-imaging light is reduced by, first, the 10 stops from the initial pass through the filter and second, by the 10 additional stops from each reflection inside the filter. The second purpose of coating is to increase transmission through the glass; the exact opposite purpose of a ND filter.

I thought the problem with filters and flare is that some of the light will reflect from the lens/camera components onto the rear part of the filter, then reflect from that side of the filter back onto the sensor. Like in the left-hand image here - LINK

So the light causing the flare has only passed through the filter once. Yes, it is diminished by 10-stops doing so, but so is your subject light - so the flare is the same brightness, proportionately, as if you'd used a clear filter.

But a multi-coated filter will reflect less light back into the camera than a single-coated filter. So it should produce less flare.

Sorry for the stupid question, but how do you tell there is a colorcast when using either a cheap filter, or a strong filter? I understand what it means, but how can I tell? Do I have to be in LR looking at the sliders? Confused!

stever1000 wrote in post #16243622
Sorry for the stupid question, but how do you tell there is a colorcast when using either a cheap filter, or a strong filter? I understand what it means, but how can I tell? Do I have to be in LR looking at the sliders? Confused!

If the colour cast is bad enough to worry about then it's bad enough to be detected by the Mk1 eyeball.

hollis_f wrote in post #16243695
If the colour cast is bad enough to worry about then it's bad enough to be detected by the Mk1 eyeball.

So if there is color cast, it can be very faint (but still easily detectable in a regular jpeg) or very dark (like a poor quality filter)?

The "color cast" being spoken of seems to show up as a magenta or purplish hue to the image not present in a shot without the ND filter.

At higher ND values like the 3.0 you're discussing here there is some risk of IR pollution where the filter is less effective at filtering IR compared to visible light. The solution is an ND filter with a hot mirror like Formatt and others sell. A tad spendy compared to your non- and multi-coated versions.