52 Cameras: Camera 56 Revisited – Canon EOS 750

Original EOS 750 post at http://exit272.com/?p=1626

With a couple of exceptions, a camera with almost no control isn’t usually one I’d shoot with again. A fellow Youtuber asked if the 750 might gain aperture control using a speed booster. A Speed Booster™ (trademark of Metabones) isn’t available for a full frame camera and not for EOS to EOS. It would mess up the flange focal distance, losing infinity focus. That plus the anti-teleconverter aspect of the Speed Booster™ is more math than I want to tackle to figure out what it would do to the image.

I don’t have a speed booster but I do have lens adapters and old lenses. What will the 750 body do if it doesn’t find an EOS lens? Most modern DSLRs have a setting that allows the shutter to work without a lens being detected for macro tubes, bellows, etc., that break the lens-body communication link. This is a much older camera with no menus but it’s worth a shot.

First up, an M42 screw mount adapter. Nothing is passed through to the camera, it just puts the lens at the right distance from the film (or sensor) plane. A fresh battery, pop on the adapter, turn it on and…

No errors. Promising. In goes a dead roll of film (great for testing transport without wasting film) and the film pre-winds like it’s supposed to. The camera body lets me “take pictures”. The 750 is from 1988 and the EOS system had only been out about a year and a half so I guess it’s not that surprising that the firmware doesn’t have a routine for failing without a lens. ROM space used to be expensive.

I have some craptastic Photoworks film (a 24 exposure roll of “Use by 11/2004” ISO 200) so I’m good to go — just gambling some developer.

I used a Helios 44-2, a beautiful Soviet-era lens. It can be tedious but one of its quirks is what I want for this experiment. It doesn’t stop down automatically. You set the aperture and a separate ring swings between wide open (f/2 in this case) and your setting. This lets you focus on a nice bright image and then rotate the ring to stop down without having to look at the lens.

The 750 does full aperture metering. There is a separate, 6 zone light meter that reads the light with the lens wide open to get the exposure value (EV) so the camera can calculate the shutter/aperture combination.

It could be implemented as a lookup table in the camera.  The bottom line is the red one.

It could be implemented as a lookup table in the camera. The bottom line is the red one.

How it works with an EOS lens. Anthropomorphizing and probably not completely accurate:

EOS body: Hey lens, what are you?
Lens: I’m a 50mm and I go from f/1.4 to f/22.
EB: Open up to 1.4 so the nice human can see what they’re doing.
L: Done.
[ Human 1/2 presses the shutter ]
EB: We’ve got focus lock. EV is just about zero. At 1/125 second I’m reading 2 stops over.
[ Human presses the shutter button the rest of the way ]
EB: Stop down to f/2.8.
[ f/2.8 is 2 stops dimmer (smaller) than f/1.4 ]
L: Done.
EB: Mirror up. Shutter fired. Mirror down. Advancing film. Open up to 1.4 so the nice human can see what they’re doing.
[ The 750 actually sucks the film back into the can rather than advancing but you get the idea ]

If the camera defaults to aperture priority, I’m golden. It’ll meter the scene and pick a shutter speed. If it does some shutter and aperture auto-exposure (AE) voodoo or shutter priority (Tv in Canon-speak), the experiment is toast. AE is bad because it can’t control the manual lens to match an aperture to its chosen shutter speed. Tv is bad because there is no feedback to tell me what shutter is chosen so I can pick an aperture.

Either I got lucky with a lot of exposure combinations or it does aperture priority. This also makes sense. When EOS was introduced, people who’d spent a fortune on the mechanical FD lenses screamed bloody murder. Canon even made FD to EOS converters with corrective lenses in them. With no way to communicate between the lens and the body, the only solution is to do aperture priority or manual (if the body lets you select the shutter speed).

Here’s my process. Turn the lens ring to wide open so the scene is bright and focus. Turn the ring to the f/stop I want and 1/2 press to turn on the meter.

Slow blinking 'P' = open up, use a tripod, or flash.  Fast = figure out over or under & adjust.

Slow blinking ‘P’ = open up, use a tripod, or flash. Fast = figure out over or under & adjust.

Helios 44-2 at f/16.  Metering at f/2, the 'P' in the viewfinder blinks indicating exposure out of range.

Helios 44-2 at f/16. Metering at f/2, the ‘P’ in the viewfinder blinks indicating exposure out of range.

Some macro shots. I’ve had the broken balsa plane and cicada wing forever. Add feathers and a seed and I have a theme. To get some depth of field, I had to stop way down. F/16 was too dark. Not bad exposure dark, just not an attractive image.

F/16 with flash was too bright.

F/16 with flash was too bright.


F/16 with some LED lights was just right.

F/16 with some LED lights was just right.


F/16.  I used flash but I was so close it was partially blocked by the lens.

F/16. I used flash but I was so close it was partially blocked by the lens.

Next I tried a Nikon adapter. It has a “Dandelion” chip for focus confirmation but the 750 ignored it completely. It works with a Canon 60D DSLR so it’s probably the age of the 750’s firmware.

Nikon 50mm at f/1.4.

Nikon 50mm at f/1.4.


Same scene at f/16 with flash.

Same scene at f/16 with flash.

I’m not sure what’s up with the flower images (ignore the dust and cat hair — that’s a different issue entirely). It might be the film — the Photoworks stuff has lost a lot of speed from age and tends to make really crummy, thin negatives. It’s also possible my notes are wrong. According to my notes, the first one is at f/2.8 but it’s so thin the scanner had to boost the gain and made it ugly and grainy just to get something.

Nikon at f/2.8.

Nikon at f/2.8.


My notes say f/11 and this looks OK.

My notes say f/11 and this looks OK.


F/16 with flash.  Exposure is all right but the colors are way off.  The wall isn't blue.

F/16 with flash. Exposure is all right but the colors are way off. The wall isn’t blue.

While writing this, it dawned on me that the bad images are under artificial light. Everything else is outside or on the sun porch. It fits the symptoms if the old film lost sensitivity to specific wavelengths.

The short answer (too late) is: The EOS 750 works well as an aperture priority camera with manual lenses.

Thanks to Salvador for asking a good question leading me to this fascinating journey.

52 Cameras: # 146 — Utility Mfg. Co. Carlton (Falcon Miniature)




I metered for box speed (ISO 80) even though the film is 44 years old so most of the shots are underexposed. Honestly, I wasn’t expecting anything because of the cross-processing so this is a pleasant surprise.
Goober pining for the fjords

Goober pining for the fjords


Quite a bit of flare.

Quite a bit of flare.


Half of the image in the video.  Jem approaches Goober.

Half of the image in the video. Jem approaches Goober.


Dramatic tree.

Dramatic tree.


Is this thing on?  Spooky how much I'm looking like my dad.

Is this thing on? Spooky how much I’m looking like my dad.




A minor tear-down to clean it and measure the aperture.
The place to start -- there are only two screws.

The place to start — there are only two screws.


The whole lens/shutter assembly lifts off to reveal…
... This felt pad which makes it light tight.

… This felt pad which makes it light tight.


I wanted to get to the back of the lens to clean it but I couldn’t figure out how to remove the shutter. It turns out it’s just sitting there. The whole stack, the face-plate, lens, shutter, and felt, are held in place with the screws.
The outer shutter opens & the inner one closes so the aperture is already covered when you let go of the lever.

The outer shutter opens & the inner one closes so the aperture is already covered when you let go of the lever.


The time lever (right in the photo above) has a tab that holds the inner shutter open.
The back of the lens board.

The back of the lens board.


The body is just a light-tight box with a knob to turn the spool.

The body is just a light-tight box with a knob to turn the spool.


Simple is good. Simple survives. Other than cleaning the lens and a little gunk in the shutter, I didn’t have to do anything. This camera works as well as it did 77 years ago.

Process Kodacolor-X as Black & White

I recently shot with an old Carlton 127 camera. The only film I had was a roll of new-old stock Kodacolor-X.

ASA/ISO 80 -- Develop by Feb. 1974.

ASA/ISO 80 — Develop by Feb. 1974.


Kodacolor-X is process C-22 film, extinct except for a couple of specialty labs who mix their own chemicals from scratch. Since I shot the film (not a precious roll of family photos found in a relative’s attic), it’s not worth the price or the wait to send it off. I’ve read here and there about cross-processing old color print film in B&W chemicals and even had some success (-ish) with Kodachrome. Worth a shot so here’s what I did:

I used Kodak HC-110 developer at dilution H. H is an unofficial mix using 1 part developer concentrate to 63 parts water. That’s the US strength developer where dilution B is 1+31.

I used a Yankee plastic tank and lower reel that can adjust for 127 film. For 127, the tank takes 420mL of solution.

Everything was done at 20C/68F. I developed for 10 minutes agitating the first 15 seconds (about 10 inversions) and then 4 inversions every minute for the remainder of the time.

One minute stop bath, using Kodak Indicator Stop at 16mL/liter, inverting the first 15 seconds (10 inversions) and then letting it sit for the remainder of the time.

Ilford Rapid fixer mixed to normal film strength (1+4) for 5 minutes using the same agitation as the developer.

I rinsed using the Ilford method: fill tank & invert 5X; Re-fill & invert 10X; Re-fill & invert 20X. I gave it an extra 20X rinse with some Photo-Flo for good measure and hung it to dry.

The base is really dark orange but Kodacolor-X doesn’t have the nasty, black anti-halation layer that Kodachrome has, and it scanned OK. Boosting the gain on the scanner brings out the noise and grain, but not too bad for what I was working with. I used VueScan software. The Canon software won’t do negatives without the film holder but I don’t have a 127 holder.

I’ll try scanning again after trying a bleaching step, soaking the film in fixer with ascorbic acid (vitamin C) added.

Kodacolor negative.

Kodacolor negative.


Inversion of the snapshot.

Inversion of the snapshot.

52 Cameras: # 144 — Argus A


I need to start wearing my glasses when I do these videos. I can’t see what I’m doing up close.


A couple of things I thought of after I finished the video:
There’s no rewind release. The same knob you pull to load the cassette is the rewind knob. It’s a good idea to check it to make sure the film tension is OK after you pull it out of your bag.

The shutter is completely uncoupled from the film transport so multiple exposures are easy/easy mistakes to make.

The working bits of the camera were clean even though the body is dusty. I had it in the bag with no lens cap and the lens got crud on it. There is some grain and scanner noise in the darker shots.

This is what happens when I forget to pull out the lens.

This is what happens when I forget to pull out the lens.


Double exposure.  1/25 second wasn't slow enough so I winged it using 'B'.

Double exposure. 1/25 second wasn’t slow enough so I winged it using ‘B’.


Nice color but the uncoated lens flares if I'm not careful.

Nice color but the uncoated lens flares if I’m not careful.


Not an exciting subject but good exposure.

Not an exciting subject but good exposure.


Trees hold still while I mess around with an old camera.

Trees hold still while I mess around with an old camera.

Random Post for 28 November 2017

I’ll start with this cartoon and get it out of the way.
I need to get one of those things that helps you make straight text.

I know it's not nice to make fun of someone's appearance or name but f__k this guy.

I know it’s not nice to make fun of someone’s appearance or name but f__k this guy.


September was safety and security awareness month at work and this is the logo they chose.
Shades of Soviet propaganda posters.

Shades of Soviet propaganda posters.


I couldn’t resist. The same words according to an on line translator.
Be Essential, Comrade.

Be Essential, Comrade.


Not to be outdone, a buddy at work pranked me in the same style. He did the spine of a manual on my bookshelf too.
Arm & Hammer & Sickle.  I didn't notice for over a month.

Arm & Hammer & Sickle. I didn’t notice for over a month.

M left this drawing for me.

M left this drawing for me.


Looks like Kid from Kid N' Play.  (Wikipedia claims fair use because it's a promo.  I'm using it in a satirical work.)

Looks like Kid from Kid N’ Play. (Wikipedia claims fair use because it’s a promo. I’m using it in a satirical work.)


Soap dispenser is appalled and angered by your lack of hygiene.

Soap dispenser is appalled and angered by your lack of hygiene.

Halloween 2017

It’s el Día de los Muertos so time to put up some Halloween images…

Woooo, scary puns!  I posted this one to Imgur and it got a "most viral" rating.

Woooo, scary puns! I posted this one to Imgur and it got a “most viral” rating.


The ears didn't stay long but Trinity was a bat.

The ears didn’t stay long but Trinity was a bat.


I was a punk rocker.  I had a cat in the 80s named Den.  That's his rabies tag.

I was a punk rocker. I had a cat in the 80s named Den and my choker is his rabies tag.