clarification for me on daylight v. tungsten filters

[grainy]

Hi folks - I think this has been gone over before but I nevertheless have doubts that I'm reading this right. (and I generally shoot b/w)
So.... could someone please verify that I am understanding the following correctly? (from Super8camera.com)

"•Ektrachrome 100D film: Is daylight balanced, so when you insert use this film, switch the camera’s filter to 'tungsten' or 'indoor' to film without the 85 filter. "

So this means that because my camera was built under the assumption that film is tungsten balanced, rather than daylight balanced, I need to set the internal filter the opposite of what it seems to say -- so it's "lightbulb" rather than "sunny" if I'm outside in the sun with Ektachrome 100D?
And what I am doing in this setting is removing the internal 85 filter, which would be desirable IF the film were balanced for tunsten. Correct?? :?:

thanks for your patience!
G

[Will2]

I share your confusion, don't feel bad. I bypass this issue by owning a Beaulieu 4008 with no filter so I have to screw it on manually. Much better glass filter this way too.

For daylight film you always want the filter NOT ENGAGED. Either inside or out, daylight or tungsten lighting. Which means you put it on the lightbulb (which means no filter needed). If you want to correct daylight film for tungsten lighting you need an 81 filter which you'd have to screw on to your lens which may also mess with your exposure depending on where your camera's exposure sensor is.

However, then we get into whether or not the cartridge is notched properly for Tungsten or daylight which effects whether or not the filter will go into place anyway. I'll let clearer heads explain that.

[richard p. t.]

Hi folks - I think this has been gone over before but I nevertheless have doubts that I'm reading this right. (and I generally shoot b/w)
So.... could someone please verify that I am understanding the following correctly? (from <a href="http://Super8camera.com" rel="nofollow" target="_blank" title="Link added by VigLink" class="vglnk">Super8camera.com</a>)

"•Ektrachrome 100D film: Is daylight balanced, so when you insert use this film, switch the camera’s filter to 'tungsten' or 'indoor' to film without the 85 filter. "

So this means that because my camera was built under the assumption that film is tungsten balanced, rather than daylight balanced, I need to set the internal filter the opposite of what it seems to say -- so it's "lightbulb" rather than "sunny" if I'm outside in the sun with Ektachrome 100D?
And what I am doing in this setting is removing the internal 85 filter, which would be desirable IF the film were balanced for tunsten. Correct?? :?:

thanks for your patience!
G

Your understanding here is entirely correct.
However, there is a further complication. Most super 8 cameras also have what is called a 'filter notch detector'. This is a pin inside the film compartment that is there to detect whether or not there is a filter notch cut in the cartridge. Tungsten film has such a filter notch (or at least should! Some colour negative tungsten cartridges have been made with no notch). Daylight and black and white film has no notch. The absense of a notch means the filter pin is depressed when such cartridges are inserted into the camera. When the pin is depressed, the camera removes the internal 85 filter from the light path. So far so good. The issue is that the filter notch reader is not connected to the asa determining circuitry of the camera, where as filter switches, filter screw and key holes are. When you flick a filter switch (or insert screw or key) the camera makes a correction in the asa of the film to correct for the absense of the light loss from the filter. For instance, insert a cartridge of 160 Tungsten film and with the filter switch set to 'sun' the camera's light meter gives exposure readings based on 100 asa - wich is a 2/3rd stop compensation for the ligth lost to the internal 85 filter. Switch the filter switch/screw/key to 'bulb' and the camera no longer makes this asa correction. Instead, the light meter gives readings based on 160 asa. The filter switch/key/screw hole is thus connected to the asa determining circuitry, allowing you to get the correct exposure when using tungsten film with and without the filter. Now, remember that the 160 tungsten asa notch is the same size as the 100 daylight notch (and this 2/3rd stop relationship is the same for tungsten and daylight caridges for all the super 8 asa speeds - the 40 t notch is the same as the 25 d notch, etc.). This is why the filter notch detecting pin is NOT connected to the asa circuitry, but the filter switch/key/screw is. With the filter switch/key/screw set to 'sun', inserting a cartridge of 160t will give the same reading as when you insert a cartridge of 100d - that is a reading based on 100 asa film. With the 160 t in the camera, when you switch the switch to 'bulb' the meter will give a reading based on 160 AND THIS USUALLY ALSO HAPPENS WHEN YOU HAVE A CARTRIDGE OF 100D IN THE CAMERA - the camera will also give a reading based on 160 asa. This is the usual case (the case with most cameras), but I don't believe it isn't the case with absolutely all cameras. To know for sure, you have to do a test. With the camera set to 'bulb', look through the viewfinder while manually depressing the filter notch pin in and out. Does the exposure reading change by 2/3rds of a stop? If it doesn't (normal case) then you should shoot using 100d with the filter switch in the sun position and let the filter notch pin take care of the filter. If it does, then it doesn't matter what position the filter switch/key/screw is in - with a daylight cartridge it will always shoot at the daylight speed (eg 100 with 100d).
So, even though you are correct that you don't want to film 100d using the internal 85 filter, you still should leave the camera's switch/key/screw on 'sun'.
But this is only true for cameras that do indeed have a filter notch reader. Otherwise, you are better off using it switched to 'bulb' and getting footage that is 2/3rds of a stop under exposed.
I hope that is not too complex!
cheers,
richard

[grainy]

Thanks guys!
Richard, I will try that test -- seems like that's the best answer for the 100d question
best regards
Grainy

[Tofek]

Thanks Richard for this great reply, I'd have a question : if I shoot Tri-X 200D/160T in a Canon 518AZ (with filter pin), I must leave the filter switch on "bulb" so it is metered as 160ASA? Is it correct that if I had put the switch to "sun" it would have been metered as a 100ASA to compensate the 2/3 stop loss, and thus overexposed by one stop?

[richard p. t.]

Hello Tofek,
What you say about Tri-x being rated as 100 asa if shot with the filte switch in the 'sun' positon is true for many camera's who's highest asa rating is 100d/160t. However the 518 can detict film rated up to 250d/400t. So in this case, its a different story.
In the case of a 518, it works with Tri-X as follows: filter switch on 'sun' - 160 asa, filter switch on bulb - 250 asa. Here's why:
Tri-X has the 160D/250T asa notch. Of course, it has no filter notch, so it is really notched as 160D, however as we know, the 160D asa notch is the same size as the 250T notch. So, on the 'sun' setting, the camera will rate Tri-X as 160 asa - and the filter notch pin will take care of deflecting the camera's internal 85 filter. On the 'bulb' setting, the camera's will most likely give exposures based on 250 asa.
richard

[Tofek]

But the 518 can''t recognize 400t/250d asa films, the highest it can get is 160t/100d (see : http://super8wiki.com/index.php/Canon_Auto_Zoom_518 ). So any 160asa film in the camera is metered as 160asa on bulb position and as 100asa in sun position, correct? Now last week I shot a TriX in sun position, which is obviously wrong (a whole stop of overexposure) and the image is perfect (maybe even a little underexposed). Where's the problem?

[richard p. t.]

Ah sorry, you wrote 518 AZ and I looked up 518 SV in the super 8 database. Yes, the Auto Zoom version of the 518 only goes up to 100/160. so yes, in the 'sun' position it should have exposed the film at 100 asa.
The Auto Zoom version of the 518 requires the mercury light meter batteries. Were you using the zinc-air replacements (wien cells)? or were you using Lithium (or another type of 1.5 volt battery)? Over voltage light meter batteries would explain it.

[Tofek]

I was using zinc-air replacement batteries, I guess 1.35V. They were freshly opened. Are these a good replacement?

[richard p. t.]

They are the best available in my opinion.
Well, if you were using the correct batteries and yet the image looks too dark (and assuming there was enough light to film with in the first place) then it doesn't look good for the camera I am afraid.
If you have since shot a roll of 100d in the camera and had great results, then you can blame the processing, but really, on then.
richard

[Tofek]

I alreay shot a roll of Orwo UN54 100Asa and it came ok. I don't remember in what position the filter was, though...Anyway this TriX roll was processed by myself, so a too short first development time could explain the little darker image. (a bit off-topic, sorry).
Nevertheless, what seems weird is that Kodak tells users to put the switch on "bulb" for E100D even though most cameras will underexpose it at 160ASA !

[Tofek]

Hello everybody,
My 518AZ is broken, so I think of buying a 518 SV. But as I look, there doesnt seem to be such a filter switch with bulb and sun positions as on the 518AZ. There's a filter cancellation key, though. Does it play the same role as the switch on the 518AZ? Does it change exposure ONLY when there is a daylight film in (=filter already cancelled) ?