Coated filter on an "uncoated" TLR taking lens

[ggray79]

Got a Minolta Autocord TLR from ebay in the mail today ("Citizen - MXV"). It has a Rokkor 75/3.5 taking lens with a lens serial number of 2252331. I cannot confirm that it is coated, but let's assume it is not. I will be shooting color negative film, e.g., Kodak Ektar 100 and Portra 160. I have a B&W UV-Haze MRC filter that I can use on a Bay 1 step up ring. Am I right that the multi-coating on the filter will offset any of the "negative" effects of using an uncoated taking lens with color film? Secondly, if the Rokkor lens is coated, will having the additional filter coatings have any effect, or are the additional layers merely redundant with no net change. I would like all the contrast and resolution that I can get out of the lens. Thanks!

 

[BrianShaw]

There are, most often, no "negative" effects of using uncoated taking lens with color film.

Be mindful to control potential flare as much as practical by using a lens hood/shade and not photographing into the sun... no matter what film is being used.

 

[grat]

Someone correct me if I'm wrong, but I was under the impression that coating is to control flare, and ghosting between elements, whereas color correction has to be done at the optical level, as the different frequencies of light refract, and thus focus, slightly differently..?

 

[Dan Daniel]

The Autocord Rokkor lenses are coated.

Multicoating or single coating afects light passing through the glass/air interface at that point. Every time light goes from one medium to another, reflections are an issue. Light that passes through a multi-coated filter does not take on any special properties that transmit to the next interface.

Certainly every chance to reduce reflections is good, but again, it is a step by step basis, not imbuing the light with properties that travel downstream.

Brian has it- lens hood is the best thing you can do. Filters or not.

 

[xkaes]

A multi-coated filter won't make anything worse, but it won't make anything better either. But it may avoid extra flare, glare & contrast reduction -- caused by using an uncoated filter.

As to your Minolta TLR, Minolta was the first Japanese lens manufacturer to apply coatings to their lenses in 1946. Chances are your camera was made after that year, so it is coated. Here's how you can find out:

http://www.subclub.org/minman/mintlr.htm

Minolta started using multi-coating in 1958 -- again, the first Japanese lens maker to do this. They referred to it as "Minolta Achromatic Coating" (the term "multi-coated" had not yet been born) -- two layers of different thicknesses applied to certain lens surfaces. The process evolved and improved over the years, but Minolta stuck with their original term -- "Minolta Achromatic Coating" -- even though it was different. Some of their lenses and filters are marked "AC" -- that's what it means.

 

[Sirius Glass]

The "negative effects" would show up if you were to aim the lens at a bright light source such as a street lamp in a dark scene or the sun and then the flare(s) or glare would show those effects. Otherwise, a difference but not a great difference and there is no reason not to use the camera. Enjoy it as it is.

 

[xkaes]

The "negative effects" would show up if you were to aim the lens at a bright light source such as a street lamp in a dark scene or the sun and then the flare(s) or glare would show those effects.

Those would show up whether a multi-coated filter was used or not. The OP wants to know if a multi-coated filter would help in these situations, and the answer is that it will not help. It's certainly better than using a single-coated or uncoated filter, but these situations require a good lens shade -- and a multi-coated lens, which is what the Minolta Autocords have.

 

[ggray79]

Thanks xkaes. My problem is I saw a comment somewhere that the earliest Autocords did not have the multi-coated lens. Mine may be one of the earliest since its fastest shutter speed is 1/400. Based on the first link below and a couple of unique features, I believe I am the Minolta Autocord RA/MXV with the printed "Citizen MXV" being positioned at the camera location where the type of shutter is normally placed. But this link indicates the shutter is an "Optiper MXS" which is the first level of Autocords per the second link below. However, that second link has a serial number list used for all Autocords (not model specific) which would suggest mine is several steps later (my serial number is 230002). The copied portion below, from another website, indicates that the "RA" model change replaced the Optiper shutter with the Citizen. It may be that my model lasted a few years with a change to the Citizen shutter coming then - a few years probably ensuring I have a coated lens.

I will be using a hood, but some online comments say the uncoated taking lens will lose some contrast and resolution even without flare and ghosting. Until I can determine that mine is coated I would like to alleviate the loss of contrast and resolution by using the B&W MRC filter - if that helps - and doesn't cause some other problems. So, I should have been more specific as to what I hope the filter will accomplish.

Meanwhile, is there any kind of test to determine if a camera in your hand has a coated lens?

https://www.blackmarketcamera.com/p...ocord-ra-mxv-120-twin-lens-reflex-camera-used


https://web.archive.org/web/20070524222556/http://www.wctatel.com/web/crye/a-cord.htm

Minolta Autocord

Overview - Virtually unknown 6x6 twin lens reflex. Made in several models, which can include variously the LVS exposure system, selenium manual meter, CDS meter, Seiko and Optiper shutters. Japanese TLRs are a dime a dozen, but the Minolta Autocord is the only variety that steadily increases in value (on every rare occasion you see one on the resale market). Why? Because it outdid the Rollei 3.5MX and Rolleicords it was designed to emulate (if you doubt this as a purpose, you will notice that the striping around the wind lever and the tripod socket are identical; you will also notice "Chiyoko" where you would expect to see F&H). These are the principal models.​ Original Autocord - Optiper shutter Autocord L - Citizen Shutter, selenium cell meter (nameplate flips up), LVS exposure system (take the reading; add the numbers on the shutter and aperture scales to match the reading). Autocord RA - Like the Original, but with the Citizen shutter

 

[Sirius Glass]

The "negative effects" would show up if you were to aim the lens at a bright light source such as a street lamp in a dark scene or the sun and then the flare(s) or glare would show those effects. Otherwise, a difference but not a great difference and there is no reason not to use the camera. Enjoy it as it is.

Those would show up whether a multi-coated filter was used or not. The OP wants to know if a multi-coated filter would help in these situations, and the answer is that it will not help. It's certainly better than using a single-coated or uncoated filter, but these situations require a good lens shade -- and a multi-coated lens, which is what the Minolta Autocords have.

They would show up stronger for uncoated lenses. That explanation was posted so the OP would understand what to look for on an uncoated lens versus a coated lens.

 

[JPD]

Someone correct me if I'm wrong, but I was under the impression that coating is to control flare, and ghosting between elements, whereas color correction has to be done at the optical level, as the different frequencies of light refract, and thus focus, slightly differently..?

That is true. Colour corrected lenses were made already in the 1700s, before photography. It was important for telescopes and then later for black and white photography, since colours focusing differently causes blur.

In the 1950's almost all lenses were colour corrected, except the meniscus lenses used in box cameras and similar. Many coated lenses were called "Color-" something only for marketing. Coating improved the contrast, though, which was more noticeable on colour prints and slides than on black and white. (It's easier to increase the contrast with b/w in the darkroom).

 

[JPD]

Thanks xkaes. My problem is I saw a comment somewhere that the earliest Autocords did not have the multi-coated lens. Mine may be one of the earliest since its fastest shutter speed is 1/400. Based on the first link below and a couple of unique features, I believe I am the Minolta Autocord RA/MXV with the printed "Citizen MXV" being positioned at the camera location where the type of shutter is normally placed. But this link indicates the shutter is an "Optiper MXS" which is the first level of Autocords per the second link below. However, that second link has a serial number list used for all Autocords (not model specific) which would suggest mine is several steps later (my serial number is 230002). The copied portion below, from another website, indicates that the "RA" model change replaced the Optiper shutter with the Citizen. It may be that my model lasted a few years with a change to the Citizen shutter coming then - a few years probably ensuring I have a coated lens.

I will be using a hood, but some online comments say the uncoated taking lens will lose some contrast and resolution even without flare and ghosting. Until I can determine that mine is coated I would like to alleviate the loss of contrast and resolution by using the B&W MRC filter - if that helps - and doesn't cause some other problems. So, I should have been more specific as to what I hope the filter will accomplish.

The Minolta Autocord should at least be single coated, and with its Tessar-type lens with only six glass to air surfaces it shouldn't be a problem at all. If you add a filter to the lens it gives the lens system two more glass to air surfaces, so it's always good to use a coated or multicoated filter so the filter doesn't cause unnecessary reflections in the lens system.

I use coated filters on my uncoated pre-war lenses as well on my coated and multicoated lenses.

 

[250swb]

It will be fine. I wouldn't put an UV filter on it day to day only a lens hood, and then keep filters for the usual yellow, orange, red, etc.

 

[JPD]

For uncoated lenses about 4% of the light is reflected from each glass to air surface, and inside the lens the reflected light bounce inside the lens before it reaches the film. This lowers the contrast. Coating improves the light transmission so less of the light will be reflected and bounce on the glass surfaces.

Using a filter adds two new glass to air surfaces to the lens, and the reflections from them can decrease the contrast and increase the risk of flare, but it will affect the image less if the filter is coated or even less if multicoated.

A coated filter can't make an uncoated lens "coated", but the filter will have less impact on the over all internal reflections if it's coated. A multicoated filter will have less impact still.

Your Minolta Autocord probably has a single coated taking lens, and using a multicoated UV filter will not make the lens multicoated. The filter will only add two more glass to air surfaces to the lens system, but as it's multicoated it will not degrade the contrast as much as a single coated or uncoated filter.

The only time an UV filter will help increasing the contrast is in an enviroment with a lot of UV light, such as on a beach, on the sea or on the mountains. For "normal" photography it isn't needed, except for maybe to protect the front element of the lens like some use it for.

The Minolta Autocord will be fine for using Kodak Ektar or Portra with or without the B+W MRC UV filter. Take test photos with and without the filter, and I'm sure you will not see a difference. It's a high quality filter, and the purpose of the MRC coating is that the filter will not degrade the results because of added internal reflections when you use it.

 

[Sirius Glass]

For uncoated lenses about 4% of the light is reflected from each glass to air surface, and inside the lens the reflected light bounce inside the lens before it reaches the film. This lowers the contrast. Coating improves the light transmission so less of the light will be reflected and bounce on the glass surfaces.

Using a filter adds two new glass to air surfaces to the lens, and the reflections from them can decrease the contrast and increase the risk of flare, but it will affect the image less if the filter is coated or even less if multicoated.

A coated filter can't make an uncoated lens "coated", but the filter will have less impact on the over all internal reflections if it's coated. A multicoated filter will have less impact still.

Your Minolta Autocord probably has a single coated taking lens, and using a multicoated UV filter will not make the lens multicoated. The filter will only add two more glass to air surfaces to the lens system, but as it's multicoated it will not degrade the contrast as much as a single coated or uncoated filter.

The only time an UV filter will help increasing the contrast is in an enviroment with a lot of UV light, such as on a beach, on the sea or on the mountains. For "normal" photography it isn't needed, except for maybe to protect the front element of the lens like some use it for.

The Minolta Autocord will be fine for using Kodak Ektar or Portra with or without the B+W MRC UV filter. Take test photos with and without the filter, and I'm sure you will not see a difference. It's a high quality filter, and the purpose of the MRC coating is that the filter will not degrade the results because of added internal reflections when you use it.

To add to what you posted: If a multicoated filter or single coated filter could make up for lenses not being coated, then no lenses would be coated.

 

[JPD]

To add to what you posted: If a multicoated filter or single coated filter could make up for lenses not being coated, then no lenses would be coated.

A 100% opaque filter would work, but then it not really a filter but a lens cap.

 

[gone]

If I'm not mistaken, all the Autocords had coated lenses. FWIW my photos w/ the best IQ and sharpness came from uncoated lenses w/ a Y. filter. The Summar and old Heliar lenses were outstanding, and nary a coating between them. They didn't flare either, but I put a hood and Y. fltr on every camera I own.

My Autocord had more contrast than my 80mm 'blad lens, but the 'blad had noticeably better resolution. On prints, it was difficult to tell them apart.

 

[xkaes]

The Autocords were Minolta's top-of-the-line cameras. Minolta started coating lenses in 1946 -- the first Japanese company to do this. So of course all of the Autocords -- which started in 1955 -- are coated.

Minolta started using multi-coating in 1958, so all of the Autocords from that point forward are multi-coated.

And a multi-coated filter will not make things better or worse on any single coated or multi-coated lens.

 

[ic-racer]

If there is significant haze on any of the surfaces, that will make the question of coating irrelevant.

 

[maltfalc]

it'll reduce purple fringing and atmospheric haze, that's about all.

 

[Dan Daniel]

Thanks xkaes. My problem is I saw a comment somewhere that the earliest Autocords did not have the multi-coated lens. Mine may be one of the earliest since its fastest shutter speed is 1/400. Based on the first link below and a couple of unique features, I believe I am the Minolta Autocord RA/MXV with the printed "Citizen MXV" being positioned at the camera location where the type of shutter is normally placed. But this link indicates the shutter is an "Optiper MXS" which is the first level of Autocords per the second link below. However, that second link has a serial number list used for all Autocords (not model specific) which would suggest mine is several steps later (my serial number is 230002). The copied portion below, from another website, indicates that the "RA" model change replaced the Optiper shutter with the Citizen. It may be that my model lasted a few years with a change to the Citizen shutter coming then - a few years probably ensuring I have a coated lens.

I don't understand all the 'RA' and such naming for Autcords, so excuse me while I don't touch that.

If the link to the Black Market Photo sale is the camera that you have now, it is set up for 4.5cm x 5cm shots, 18 per roll. Looks as if you could find a counter disk that says '12' and remove the internal mask and do 6x6 images. Very unusual model. From what I can see, the viewfinder screen is NOT masked out for the smaller shots, so be careful.

If you open the early cameras labeled 'Optiper,' the shutter will be labeled Citizen. Your camera has a meter focus scale, so I bet it was for Japanese market, not US military bases or export. Going by the serial number, your camera should be a much later model. I bet that when they wanted to try the alternative framing and counter dial, they set up a special project run using old cameras, shutters, etc. Sort of a summer intern project room type of thing? 'Here are boxes of old stuff, make us something!' Putting Citizen on the front rather than Optiper avoided some confusion. Based simply on serial number of the body, this should be a mid-late series Autocord.

There is a guy in Oregon, Karl Bryan, who has seen pretty much every Autocord, I bet. I suggest you drop him a note, ask him what he can tell you about the counter. I'll send you his email in a DM so that he doesn't get spammed out in forums.

 

[ggray79]

I don't understand all the 'RA' and such naming for Autcords, so excuse me while I don't touch that.

If the link to the Black Market Photo sale is the camera that you have now, it is set up for 4.5cm x 5cm shots, 18 per roll. Looks as if you could find a counter disk that says '12' and remove the internal mask and do 6x6 images. Very unusual model. From what I can see, the viewfinder screen is NOT masked out for the smaller shots, so be careful.

If you open the early cameras labeled 'Optiper,' the shutter will be labeled Citizen. Your camera has a meter focus scale, so I bet it was for Japanese market, not US military bases or export. Going by the serial number, your camera should be a much later model. I bet that when they wanted to try the alternative framing and counter dial, they set up a special project run using old cameras, shutters, etc. Sort of a summer intern project room type of thing? 'Here are boxes of old stuff, make us something!' Putting Citizen on the front rather than Optiper avoided some confusion. Based simply on serial number of the body, this should be a mid-late series Autocord.

There is a guy in Oregon, Karl Bryan, who has seen pretty much every Autocord, I bet. I suggest you drop him a note, ask him what he can tell you about the counter. I'll send you his email in a DM so that he doesn't get spammed out in forums.

Thank you all for the great info! Mine is set for 12 and did not include the stuff to make it 18. The second link above points to 1957 for the changeability to 4.5 x 5. Based on comments above that seems to point to single coating if pre-1958. However, the serial number points to the time-frame of the Autocord Seikosha-MX which first appeared in 1958, so mine probably has multiple coating. Thanks again!