Reversed Canon 28 FD Question

drdane

I just bought this lens on ebay, and was expecting its aperture to be wide open when off camera (like when reversed), but it's sitting at less than half open. By this I mean that when looking at the aperture from the front of the lens, its opening diameter is about 1/3 of the total that should be available. The opening doesn't respond to rotating the aperture ring, but does close down to almost nothing (f22?) when the rear end cap is installed.

Does anyone know what "normal behavior" is for this lens when it's off-camera?:scratch

I want to use it reversed on my D-Rebel for macro, being able to set the aperture manually from 2.8 to 22, a la sirsloop's crazy macro posts on one of these forums about 2 weeks ago.

I'm going to meet with a friend who has a T90 body in a couple days, so I check out it's function on-camera.

Impatiently waiting for your words of wisdom . . .

DoctorIt

Funny enough, I got my hands on a Sigma 28 for Canon FD just yesterday. And I'm also scratching my head, I could swear that FD lenses had manual aperture rings. Guess I was wrong.

drdane

DoctorIt wrote:

Funny enough, I got my hands on a Sigma 28 for Canon FD just yesterday. And I'm also scratching my head, I could swear that FD lenses had manual aperture rings. Guess I was wrong.

They do, really! Well, most of the time, at least. I remember my old Pentax lenses functioning that way, and I still have a Vivitar on a Minolta that gracefully moves through the range of 2.8-22 openings when off camera, which is what we macro nuts are looking for.

Do you mean that there is no aperture ring on that Sigma???

DoctorIt

drdane wrote:

They do, really! Well, most of the time, at least. I remember my old Pentax lenses functioning that way, and I still have a Vivitar on a Minolta that gracefully moves through the range of 2.8-22 openings when off camera, which is what we macro nuts are looking for.

Do you mean that there is no aperture ring on that Sigma???

there is, but like your Canon, it has no effect on the actual aperture, ie. when looking through the lens, moving the aperture ring has no effect on the blades in the lens.

let's not mix mounts here, we're talking about Canon FD. I also have "old" lenses of the Nikkor variety that work fully manually and are great for reverse macro. that's why I'm so surprised about this FD lens.

mikeb380

drdane wrote:

They do, really! Well, most of the time, at least. I remember my old Pentax lenses functioning that way, and I still have a Vivitar on a Minolta that gracefully moves through the range of 2.8-22 openings when off camera, which is what we macro nuts are looking for.

Do you mean that there is no aperture ring on that Sigma???

As I sit here with my 28mm FD lens, I checked the aperture opening and it works at all fstops off the camera. The opening at which you are looking is correct, the 2.8 aperture doesn't open "all the way". What you see is the barrel of the lens and it gives the illusion that the aperture can be larger. It never opens "all the way." What you think is part open is all the way open. I just re-read your post andchecked with the rear cap off. The lens is always wide open, no control of Fstops. I guess you could cut out the bottom of the cap and pretend it is a sunshade. As you say, it seems that the stops could be adjusted as you want to use it.

I just checked my 200 FL lens andon the bottom near the locking ring are marks, A & M. if set on A the opening stays full aperture but on the M setting the aperture changes as you turn the ring. I guess Canon didn't wantus to use the inverted FD lenses for macro?

I hope this didn't confuse you. It looks confusing but is the best way I know to tell you.

Any lens for the FD canons has to have an aperture ring, there is no other way to set the Fstops. None of the cameras taking FD lenses were auto except the F1 if you got a finder, I can't remember the name of it. With that finder you set the aperture ring on "A". Oh, the A1 was also a program camera as was the AE1 Program. But the lenses were the same, they had an aperture ring.

DoctorIt

mikeb380 wrote:

As I sit here with my 28mm FD lens, I checked the aperture opening and it works at all fstops off the camera. The opening at which you are looking is correct, the 2.8 aperture doesn't open "all the way". What you see is the barrel of the lens and it gives the illusion that the aperture can be larger. It never opens "all the way." What you think is part open is all the way open.

I hope this didn't confuse you. It looks confusing but is the best way I know to tell you.

Yeah, you definitely didn't help!

Don't know about dane, but my question was more the other way - I realize it's wide open and there's lens barrel in there when I look through. I want to know why it doesn't close down like my Nikkor (not even that old) when I turn the aperture ring to f/22.

sirsloop

make sure you put the lens in the lock position! The aperture flipper won't work in the unlock position... so "lock" the lens, set the aperture to f/22, then try pushing the little lever. I had the same thing happen to me.. took a few minutes to figure out - then I felt like a newbie fool cause I had never used an FD lens before! HAHAHAH!

DoctorIt

sirsloop wrote:

make sure you put the lens in the lock position! The aperture flipper won't work in the unlock position... so "lock" the lens, set the aperture to f/22, then try pushing the little lever. I had the same thing happen to me.. took a few minutes to figure out - then I felt like a newbie fool cause I had never used an FD lens before! HAHAHAH!

Bingo!

I knew there must be some sort of trick to the little levers sticking out the mount end!!

Thanks sloop

SCS_Photo

DoctorIt wrote:

Bingo!

I knew there must be some sort of trick to the little levers sticking out the mount end!!

Thanks sloop

If you're not happy with it, I have a Vivatar 28mm f/2.0 that I would like to part with. Its pentax fit, but has an extra flange that I'd have to dremel off to use with my *ist DL, and I'm not really wanting to do that.

DoctorIt

SCS_Photo wrote:

If you're not happy with it, I have a Vivatar 28mm f/2.0 that I would like to part with. Its pentax fit, but has an extra flange that I'd have to dremel off to use with my *ist DL, and I'm not really wanting to do that.

thanks, this one will do just fine now that I now the trick. feel free to put it up in the flea market though... I'm sure there's others here who'd love to try out some reverse macro.

drdane

sirsloop wrote:

make sure you put the lens in the lock position! The aperture flipper won't work in the unlock position... so "lock" the lens, set the aperture to f/22, then try pushing the little lever. I had the same thing happen to me.. took a few minutes to figure out - then I felt like a newbie fool cause I had never used an FD lens before! HAHAHAH!

Sirsloop to the rescue - well, almost. I'm not understanding what you mean by "unlock" the lens, nor which "lever" you're referring to. I've pushed & pulled everything that remotely looks like a button or lever, with no success. Any further clarification you might offer would be appreciated.

I emailed the guy I bought it from and this was his reply, "Thank you for the question. That is normal with this Canon lens. I will reply further later."

Sincerely yours,
Clueless:cry

sirsloop

The FD lenses apparently had a locking feature built into the lens, instead of the locking feature being built in the body like on EF mount cameras. When you picked up a lens to put on a body, you had to rotate the locking ring thats around the camera side of the lens into the unlock position, take the rear cap off, put the lens on the camera, them re-lock that ring to hold the camera on the body. The aperture does not work if that ring isnt in "lock" position. You can see that locking ring below - towards the rear of the lens (backwards...its facing forward as shown). Its got the read dot and "unlock partially showing.

Now once thats locked, you can adjust the aperture manually. Modern camera's all control the aperture electrically, where as FD mount camera's simply had a mechanism that pushed against the aperture "metal thing" that sticks out the back of the lens. You can see it clearly on the back of the lens there... Kinda looks like a sideways Y with the "v" part filled in. Its the larger piece of metal that sticks out there.

Now... if this is not an FD mount lens, you are on your own!!! HA!

drdane

sirsloop wrote:

You can see that locking ring below - towards the rear of the lens (backwards...its facing forward as shown). Its got the read dot and "unlock partially showing.

Now... if this is not an FD mount lens, you are on your own!!! HA!

Thanks for the tutorial! It looks just like that, but doesn't have any lettering for lock or unlock. I can't budge the thing at all. There's a rectangular chrome button in that rear ring, which depresses slightly, but no help from pushing on that, either - this must be the door to the "chamber of secrets" or something . . . Maybe there's a curse on it?

Any other clues? (don't give up on me yet!:D )

sirsloop

heh heh... yeah this is like the mystical lens! HA!


with your left hand grip that locking ring and depress the button on it with your left index finger. Grab the body of the lens with your right hand and attempt to twist it. The locking ring should remain still and the lens should pivot around about 90 degrees. Give it some force both ways...

If you can, post a photo of the lens so we can decipher this little bastard

drdane

Here's the guilty party (unless, of course, it's me:D )

drdane

Here's another view. It wouldn't allow me to post two, even though they were small files .

sirsloop

ya... thats basically the same lens that I have. When that back ring with the chrome button is one way, its locked - the other... unlocked. Do you have a rear lens cap for it? If so, how do you keep it on? The locking mechanism holds it on there...

drdane

Here's the ass end. The cap has a slot that engages the silver thing on the upper left, between the two red spots. It rotates CW about 15-20 degrees. (This movement closes the aperature to a very small opening.)

The cap must also engage something else, as I can't move the pin without using the cap. I can't find anything else, however.

The rear "ring" may not be a movable ring at all, as I notice it doesn't have a grooved grip like yours does.

sirsloop

yeah... so you have gotten it to work!! The aperture on this lens does not stay closed by itsself... which is good! You have to manually push that lever down to close the aperture. This is a benefit for two reasons:

1. Its a helluva lot easier to focus through a f/2.8 aperture than a f/22 aperture
2. After you get the focus dialed in, you can flip that lever with your pinkey and instanly widen the DOF for the photo.

drdane

sirsloop wrote:

yeah... so you have gotten it to work!! The aperture on this lens does not stay closed by itsself... which is good! You have to manually push that lever down to close the aperture. This is a benefit for two reasons:

1. Its a helluva lot easier to focus through a f/2.8 aperture than a f/22 aperture
2. After you get the focus dialed in, you can flip that lever with your pinkey and instanly widen the DOF for the photo.

That lever (if you are referring to the silver gizmo that the cap engages) won't be flipped with anyone's pinky, as it is recessed and has to be moved with the cap. Cutting a hole in the rear cap would allow for this.

However, it doesn't seem to be fully open to f2.8. When I hold this lens reversed, it gives a noticably darker view than my 18-55 kit lens reversed and set at about 28mm (where it is about f4.5) .

When I do a comparison metering (time is all I get) the FD reads 1/8 and the EF-S reads 1/20, which seems to confirm that visual perception.

Thanks for your help with this . I will see what else I can find out, and might have to get a different lens to have something really workable. I will let you know how it goes.

sirsloop

I guess im confused as why this one isnt working the same as mine. The layout of all the stuff on the back there look identical!! Once you get a lens that you can flip the aperture closed like that... its THE HOT SETUP for an ultra budget macro lens!

drdane

That's two us us! I'll see what the seller has to say, and maybe check with a camera repair shop as well.

More later!
Dane

DoctorIt

drdane wrote:

That's two us us! I'll see what the seller has to say, and maybe check with a camera repair shop as well.

More later!
Dane

Dane, I'm pretty sure the lens is fine! I'm guessing you're being waaaay too nice to it! If I have some time today, I'll try to take some photos of a step-by-step for you.


And to answer a previous question: you can only attach one file per post (uploading attachments hogs space on dgrin servers - boo!). However, you can link as many you like from wherever you host them (it's the preferred way). If you don't know what I mean, go here: how to post images.

drdane

DoctorIt wrote:

Dane, I'm pretty sure the lens is fine! I'm guessing you're being waaaay too nice to it! If I have some time today, I'll try to take some photos of a step-by-step for you.


And to answer a previous question: you can only attach one file per post (uploading attachments hogs space on dgrin servers - boo!). However, you can link as many you like from wherever you host them (it's the preferred way). If you don't know what I mean, go here: how to post images.

Yeah, I'm a nice guy, but I used a few pounds of force trying to move the mystery lock ring. I did, however, stop short of getting out a couple pair of channel-lock pliers - do you think I should give that a try? Or maybe I could borrow that jackhammer Ziggy used to clean his sensor?

Latest News Flash! On closer inspection, I made an astounding discovery - the black outer ring (rear view in recent post) is screwed to the silver ring just inside it with no less than 3 screws. It ain't likely to rotating any time soon - even with the channel-locks!

Anyway, what I have is a different critter, the nature of which is yet to be determined. Rather than waste your time posting a step by step I can't use, why don't you just go the extra mile and send me your sigma?:D (I do appreciate your offer, however!) What is the filter thread size on that 28 Sigma, BTW?

Thanks for the link on posts. My pea-brain assumed that if one pic of 145KB could be attached, then two of 70KB size would work as well. Does it matter what size the linked pics are?

Thanks for your support, Erik!

DoctorIt

drdane wrote:

Thanks for the link on posts. My pea-brain assumed that if one pic of 145KB could be attached, then two of 70KB size would work as well. Does it matter what size the linked pics are?

Thanks for your support, Erik!

You're welcome, and I'll answer your easy question: nope, doesn't matter what size, only 1 attachment per post.

I'm really puzzled by your lens. It's a Canon, right? You'd think that one would be the easiest! I hope this works out for you, but sorry, the Sigma is staying here - I have lots of use for it in my lab.

drdane

DoctorIt wrote:

I'm really puzzled by your lens. It's a Canon, right? You'd think that one would be the easiest! I hope this works out for you, but sorry, the Sigma is staying here - I have lots of use for it in my lab.

Here's a mug shot of the little bugger. I left the rear cap off so you could see the widest aperture I can get - pretty feeble IMO. According to the f-stop formula (focal length/f-stop = aperture diameter) the opening should be 10mm at f 2.8 - not even close. It does look wider from the rear element, but still not 10 mm. Sigh. :cry

Now you've got my curiousity up - what kind of "lab"? Are you trying to clone the 1D MkII?

DoctorIt

drdane wrote:

Here's a mug shot of the little bugger. I left the rear cap off so you could see the widest aperture I can get - pretty feeble IMO. According to the f-stop formula (focal length/f-stop = aperture diameter) the opening should be 10mm at f 2.8 - not even close. It does look wider from the rear element, but still not 10 mm. Sigh.

yup, definitely stuck. Sloop already gave a great set of instructions, so don't know how else to help over the forum.

Now you've got my curiousity up - what kind of "lab"? Are you trying to clone the 1D MkII?

no cloning. I play with fluids and laserbeams.

sirsloop

well that's a f/2.8 max aperture lens... so the aperture blades dont even move when its set at f/2.8!! That looks like its pretty small..somewhere around f/11-f/18 i bet...

sirsloop

[FONT=Geneva, Arial, Helvetica, san-serif]I used to play with [/FONT][FONT=Geneva, Arial, Helvetica, san-serif]shear banding in wormlike micelles, nanostructured polymers as biomaterials back when I was a kid!
[/FONT]

DoctorIt

sirsloop wrote:

[FONT=Geneva, Arial, Helvetica, san-serif]...back when I was a kid!
[/FONT]

I know - that's the great part, I'm getting paid for it, and a phd at the end!

mikeb380

Ok, Here is what the Canon FD user guide says:

. A safety mechanism is incorporated which prevents movements of the diaphragm blades and breech-lock ring when the lens is dismounted.
In order to make the various mechanisms function, when the lens is dismounted, perform the following. Turn the breech-lock ring, so that it is in the same position as when the lens is in mounted position, while pressing the mount lock pin with a small object, like a penci. The mount lock pin is situated below the breech-lock ring.

The pin is the silver thing hanging out of the lock ring next to a round peg. Push the pin up into the lock ring as you open. I did it, it works,



Dane, you have the latest version of the FD lenses. It has the black locking ring and the earlier lenses have a chrome like ring. In the photo you can barely see the pin sneaking down for a peek. I hope this helps more than my earlier efforts. I learned also.

Cheers
Michael dunno