Canon SL39.3C Filter

[7Szuser]

I am a collector of Canon rangefinders and I was wondering if anyone can tell me the difference between a Canon UV filter and a Canon SL39.3C Filter? I like to put original canon filters on my lenses for the time period, however, I can not always find just UV filters. Thank you

 

[John Shriver]

I think SL39.3C is a skylight filter, rather than a UV. Wratten 2A? Slightly warmer than a UV filter. For Kodachrome to reduce blue haze, but a perfectly fine substitute for a UV filter.

The UV filter would be a Wratten 1.

 

[7Szuser]

Thank you John for the information. The warmness is not as noticeable as a Skylight 1A and appears just right for Kodachrome without warming too much.

 

[airds]

filters

filters

Info leaflet scans as supplied with Canon filters - seems to indicate it's equivalent to a U.V.

 

[7Szuser]

Airds, Thank you for the instructions. I also found this on the web which explains JIC and the SL39.3C.

The number of a Japanese Industrial Standard (JIS) consists of an English letter symbol and four(4) or five(5) digits number. The number may have part number(s) following the 4-5 digits one and a hyphen "-." The English letter symbols showes 19 technical areas such as A for "Civil Engineering and Architecture", X for "Information Processing." Of the number, the first two digits show a prescribed division of sub-technical area and the last two are given freely.


Figure. JIS Symbol and Classification (Coverage items)

 

[CanonRFinder]

HI,

Pre war Canon RF filters were not marked at all just a peice of unmounted round glass but some did have the word "Seiki" on the edge. The post war filters didn't change until shortly after the introduction of the model IIB in April 1949. A coloured stack of five "drop-in" filters were introduced and these were only marked on the side "Series IV" and the company name but the identification of the filter was on a peice of paper placed with that filter. These were identified as

1. Y1-2x = Light Yellow
2. Y2-2x = Medium Yellow
3. RO-3x = Orange
4. GO-4x = Green
5. R1-5x = Red

and there was a spot in the stack for a "UV" filter but it is rare to find one in situ. There was also a set of Series VII filters.

In 1955 Canon introduced the flat screw in filters, also in coloured stacks. These were marked on the filter rim as

1. Y1 = Light Yellow
2. Y2 = Medium Yellow
3. R1 = Red
4. G1 = Green
5. O1 = Orange
6. UV = Ultra Violet

These came in sizes 34mm, 40mm, 55mm and 58mm.

In 1961 Canon changed to the JIS code of marking as you indicated in your entry above. These filters also came in coloured filter stacks. Here after the filters were marked

1. SY44.2C = Light Yellow
2. SY50.2C = Medium Yellow
3. SR60.2C = Red
4. MG55.C = Green
5. SO56.2C = Orange
6. SL39.3C = Ultra Violet

Conversion A & B along with SKYLIGHT, ND4 and ND8 were introduced at the same time. There are thin and thick flat filters as I call them. 34mm size filters was discontinued after 1961.

In 1965 Canon dropped these codes and reverted back to a version of the 1955 ID on the filters as I think that the 1961 coding may have confused photographers and really didn't tell them what coloured filter it was...just my hypothesis.

Always had a soft spot for these coloured filter stacks. I think these are unique to Canon.

Peter K

 

[7Szuser]

Thank you Peter, I appreciate the information from you, John and arids for assisting me in learning a little history of canon filters. I enjoy being able to use a product and understand why it was constructed or marked in a particular way.