John Bragg
Well-known
As a longtime user of compact 35mm cameras, espescially those with film speed automatically set like Mju I and Mju ii, I had been frustrated with only having the option to use the box speed on films. As I invariably shoot ISO 400 film at Ei 200, this was not satisfactory for me. I think of Manufacturers Box Speed as the Serving Suggestion and personal Ei as the Family Recipe. So, how to fool an auto everything camera into re-setting film speed and regain control ? I use a system that I describe as scrape and tape to re-code the film cassette. For over 10 years this has proven very successful. It involves scraping away 2 segments of the Dx code with a sharp blade and adding an additional segment with electrical tape. I have never had a problem with this modification of my cassettes and it takes about 2 minutes to do one cassette. It occurred to me that this system is far more flexible than I had envisaged since in use you can effectively re-set the speed on the fly. Simply by re-positioning the single piece of tape, the cassette can be instantly re-coded as Ei 200 800 or 1600 ! It is amazing how these thoughts come at 1am in the morning when you can't sleep. I thought I would share this simple system and hopefully it will be useful. Here is a photo of a cassette thusly modified and below is a link showing how to read Dx codes
Dx Re-Coding. by E.J. Bragg, on Flickr
Here is a link to how to read Dx Codes https://en.m.wikipedia.org/wiki/DX_encoding
Dx Re-Coding. by E.J. Bragg, on FlickrHere is a link to how to read Dx Codes https://en.m.wikipedia.org/wiki/DX_encoding
brbo
Well-known
On the fly?! Seems a LOT of work to rewind, recode, reinsert and advance the film to last position on an all-auto compact camera.
And, why?
And, why?
aldobonnard
Well-known
Pretty cool tip.
And for those who are not so confident with scraping, you can modify your film box with a DX Recoder label. Firstcall UK still have them, http://www.firstcall-photographic.co.uk/firstcall-dx-recoder-labels-iso-1600/p750
And for those who are not so confident with scraping, you can modify your film box with a DX Recoder label. Firstcall UK still have them, http://www.firstcall-photographic.co.uk/firstcall-dx-recoder-labels-iso-1600/p750
John Bragg
Well-known
Where do you get the rewind bit from ? The intention is to be able to shoot the whole cassette at a given speed with the facility to instantly choose what that speed should be on the point of loading by simply re-positiioning the single piece of tape.
Regards,
John
infrequent
Well-known
What kind of tape is that? I have been exploring this option myself but unsure what would be reflective enough to mimic silver/metal (aluminium foil?) and absorptive like black. Ofc the other problem I have is that my Big Mini has no way of confirming if tweaking the DX code actually worked. Will cross that bridge when I get to it.
John Bragg
Well-known
Ordinary electrical tape. Any tape that insulates will do. But the beauty of this system is that if you have coded a cassette for Ei 200 but suddenly decide to push the film, you can simply peel off the single piece of tape and reposition as needed. Move it one step left and it is Ei 800. Move it again one more step left and it becomes Ei 1600. Remove it and it is Ei 3200. Versatile yes ?
Dante_Stella
Rex canum cattorumque
Wouldn't it just be easier to find the meter eye and cover half of it with tape or the whole thing with an ND0.3 gel?
brbo
Well-known
Sorry. Misunderstood "on the fly" bit, obviously.
brbo
Well-known
No. And it would be much uglier, too.
John Bragg
Well-known
Very imprecise if it worked at all.
fuji645
Established
Another solution would be to adjust the compensation dial on your camera plus or minus to arrive at the higher (or in your case) lower E.I. For example, if you are shooting Tri X at 200 (where the ISO is 400), than you would move the compensation dial 1 stop which would give you an effective E.I of 200. Does that make sense or am I missing something?
brbo
Well-known
Plus I'd also like to read about Dante's way of tricking the meter to read more light than there really is (to achieve the same as rating iso400 film as iso800). Still easy?
Missing exp. comp. dials on compact p&s cameras?!
John Bragg
Well-known
You are missing something. This is a solution aimed at auto only cameras with no compensation dial or any other manual input apart from Dx contacts in the film chamber. Usually point and shoot like Mju series.
Dwig
Well-known
Right.
Dante's method will work well when you want to rerate the film to a lower IE, but can't handle situations when you want to push the film to a higher IE.
It should be noted that this will not work well with all DX cameras. A number of low end DX-only cameras did not support the full range of DX codes.
Quite a number will test only one patch and then set either ISO 100 or ISO 400 depending on whether that patch is insulated or conductive. If insulated they set 100 (a "safe" fall-back when non-DX film was used) and if conductive they assume 400. These cameras can't set 50, 200, 800, 1600, or any of the factional stop speeds in between.
Dante_Stella
Rex canum cattorumque
That's true. Lowering the ISO is easy by fooling the camera's meter; if you take apart old cameras, many of them simply used modifiers over the CDS cell like slits (you can actually see it in old p/s cameras through the eye above the lens). Others, like the Polaroid pack cameras, used step wedges.
John, BTW, a 0.3 ND gel is more consistent than the meter in most compact cameras - and I can tell you from experience that putting one on a meter cell works.
As to raising the ISO, that will indeed require re-rigging the DX codes. Looking at the mju-ii I have here, it may not be all that complicated to wire up DIP switches to the contacts.
Dante
johannielscom
Snorting silver salts
Dante, the Mju-II is already crazy money on eBay et. al. but if you manage to make that an easy DIY modification, the prices might absolutely skyrocket