How Good Are Hoya HMC Multi-Coated Filters

Same old saw, verse 347

• Use any solvent or detergent in unbelievably tiny quantities.
  
• Never immerse any part in a solvent unless you've taken it apart for rigorous cleaning and mean to do so
   
  
• Never let a solvent/cleaner seep into the edges of a filter, always apply carefully on a damp, lint-free cloth
  

The usual filters are, as I understand it, two pieces of glass with a gelatin filter in between, all put together with optical quality cement.

 

As I understand it, some solvents, like alcohols or ketones, could dissolve the cement.

 

Some years ago, I thought about taking one apart, and replacing the gelatin filter.

(I had a Wratten 87 gelatin filter and some IR film. I never did, though.)

 

Water and detergent should be good for getting abrasive dust off without scratching,

even if held on with a grease or oil.

- Cemented filters haven't been common for over 50 years. The only exception being polarisers.

Nearly every good quality round filter sold these days is 'dyed in the mass' glass, which is totally impervious to common solvents. That's certainly true of Hoya filters that used to be advertised as 'dyed in the mass'. However, it's such a common thing these days that they no longer even bother to mention it.

Use a 'lint-free' cloth, microfibre cloth or any other bit of old rag that comes to hand, but don't then complain when micro scratches from embedded grit appear on your lens or filter. OTOH you can use a fresh lens tissue and throw any dust and grit in the bin after use.

- Cemented filters haven't been common for over 50 years. The only exception being polarisers.

 

Nearly every good quality round filter sold these days is 'dyed in the mass' glass, which is totally impervious to common solvents. That's certainly true of Hoya filters that used to be advertised as 'dyed in the mass'. However, it's such a common thing these days that they no longer even bother to mention it.

 

Use a 'lint-free' cloth, microfibre cloth or any other bit of old rag that comes to hand, but don't then complain when micro scratches from embedded grit appear on your lens or filter. OTOH you can use a fresh lens tissue and throw any dust and grit in the bin after use.

It was 40 years ago when I thought about that, and the filters that I had were more than 10 years old.

Series VI if that helps.

But I hadn't realized the change over those years.

There is a large set of organic dyes which can go into plastic and gelatin filters, but can't go into glass.

But if you can make an equivalent filter in dyed glass, that is probably better.

"There is a large set of organic dyes which can go into plastic and gelatin filters, but can't go into glass."

- That's true, and indeed I believe that some corrections like A to D and D/A can be more accurately achieved with gel or plastic filters. However, the common contrast filters - yellow, orange, red, YG, etc. don't require a precise spectral curve and are (apparently) easily made in bulk glass.

Dyed in the mass is probably an easier manufacturing process these days. There's only one sheet of glass to cut and polish to plane-parallelism and no cementing stage.

I think I didn't choose Hoya for my glasses, as they have high dispersion.

(That is, chromatic aberration.) It is especially noticeable with some unusual

light sources that have both red and close to UV blue, such as LEDs.

Reminds me also, there was an anti-reflection coating that my optometrist

recommended that was very good, but the residual reflection was bright pink.

I now have one that isn't quite as good, but the reflection is dark green,

and so less noticeable.

I think I didn't choose Hoya for my glasses, as they have high dispersion.

(That is, chromatic aberration.) It is especially noticeable with some unusual

light sources that have both red and close to UV blue, such as LEDs.

 

Reminds me also, there was an anti-reflection coating that my optometrist

recommended that was very good, but the residual reflection was bright pink.

 

I now have one that isn't quite as good, but the reflection is dark green,

and so less noticeable.

Hoya makes lenses from various materials and coatings. My prescription isn't terribly strong, so my lenses don't have the highest refractive index material. So I have no such problems. My prior glasses were Zeiss. I prefer Hoya, but only by a small margin.

I sold Hoyas in the 70s and 80s. Damn good. BTW, did Hoya make Canon's filters back then? (I'm clueless there)

Yes, up until 1994.

Hoya's filters have been made under licence for a number of years by Tokina Lens Co. Up until 1994 Hoya also manufactured filters for Canon and Nikon.

The glass across the range is superb, but very much so in the upper echelon of ultra-high quality digital filters. If you want something snazzier, I'm sure B+W's uber-pricey but also unquestionable filters will fit the bill, especially for lenses with calcium fluorite, ED, ELD or aspheric glass — particularly at the front.

I did buy an IR720 filter from an ebay seller in China, mostly for fun, and not

serious work. The cost including shipping was likely less than the shipping cost

for many US sellers.

I also bought a big bag of mostly UV filters in various sizes from a nearby Goodwill store.

Especially useful for lenses bought for low prices, such as from the same Goodwill store.

(Goodwill stores have their own auction site, shopgoodwill.com, in addition to putting items

up on eBay. Buying from a nearby store saves on shipping costs.)

I do a lot of photography for fun, and playing around with different cameras and lenses,

bought for low prices, is part of the fun.

I agree with Rodeo Joe regarding the cleaning: (AUS) I use "washing up liquid" and I have done for years. That's the liquid put into water, in a kitchen sink for hand washing the dishes -it makes "soapy water"

Maybe the confusion/concern was it meant "dishwasher liquid" i.e. the liquid put into a dish-washing machine, and that would be very bad to use.

Mostly all my the lens threaded filters are Hoya. They're all fine and some a very old.

WW

I agree with Rodeo Joe regarding the cleaning: (AUS) I use "washing up liquid" and I have done for years. That's the liquid put into water, in a kitchen sink for hand washing the dishes -it makes "soapy water"

 

Maybe the confusion/concern was it meant "dishwasher liquid" i.e. the liquid put into a dish-washing machine, and that would be very bad to use.

 

Mostly all my the lens threaded filters are Hoya. They're all fine and some a very old.

 

WW

Plain old dishwashing liquid, definitely not the caustic stuff you pour into the dishwasher after the Sunday roast!

Liquid soap is also fine.