Bronica EC mirror's bumpers

[wakks]

I'm trying something, I know it's not ultra precise, but :

1 : with my 3d printed bumper and the GG, this side (like others says, the "good" side) i CAN'T reach infinity


2 : with the same 3d printed bumper and the GG on the other side, it seems i can reach infinity

 

[reddesert]

The frosted side of the focusing screen is supposed to go down. If it only reaches infinity with the frosted side up, that means you're compensating for another error somewhere. I assume that "reaches infinity" means that the focusing screen agrees with the ground glass or tracing paper on the film rails.

I don't understand why switching the lens focusing helical made a difference. Did you identify what was wrong with the helical? Just to be sure, be aware that the focus scale is read at an indicator mark that's about 1:30 o'clock when viewed from the front, not 12 o'clock like most cameras.

I don't think it is possible to measure the angle of the mirror accurately enough with a protractor to set the focus correctly. Since all of these cameras are old, I wouldn't trust measuring the bumper diameter or mirror angle on one camera and transferring it directly to another camera, without checking that the focusing screen, film rails, and focus scale on the helical all agree. That's what you're doing, so good, but I don't understand why the focus scale was off and the focusing screen needs to be flipped, which makes me think there is some unresolved problem.

 

[wakks]

The frosted side of the focusing screen is supposed to go down. If it only reaches infinity with the frosted side up, that means you're compensating for another error somewhere. I assume that "reaches infinity" means that the focusing screen agrees with the ground glass or tracing paper on the film rails.

I don't understand why switching the lens focusing helical made a difference. Did you identify what was wrong with the helical? Just to be sure, be aware that the focus scale is read at an indicator mark that's about 1:30 o'clock when viewed from the front, not 12 o'clock like most cameras.

I don't think it is possible to measure the angle of the mirror accurately enough with a protractor to set the focus correctly. Since all of these cameras are old, I wouldn't trust measuring the bumper diameter or mirror angle on one camera and transferring it directly to another camera, without checking that the focusing screen, film rails, and focus scale on the helical all agree. That's what you're doing, so good, but I don't understand why the focus scale was off and the focusing screen needs to be flipped, which makes me think there is some unresolved problem.

i've checked helical, and it's good it focuses to infinity with tracing paper (checked with a lupe):


so now i'll try to find the axe of mirror with printed protractor taped on a side, if you have better ideas your welcome

 

[wakks]

I did a check again and i don't understand what does it mean :/
1 > with the original ground glass (frosted toward lens)


2> with tracing paper

 

[cramej]

I'm trying something, I know it's not ultra precise, but :

1 : with my 3d printed bumper and the GG, this side (like others says, the "good" side) i CAN'T reach infinity

This means the mirror isn't aligned correctly or the waist level GG needs to be adjusted.

I did a check again and i don't understand what does it mean :/
1 > with the original ground glass (frosted toward lens)


2> with tracing paper

If you can focus at infinity using a GG or tracing paper here, your GG is not at the film plane. You need to have the back on, insert removed to be able to put the GG at the film plane. In these photos, it is directly on the camera body which is a few mm forward of the film plane. Thus, you are unable to focus to infinity where infinity is supposed to be on the helical.


The waist level GG and film plane GG have to agree at infinity. It's not likely that the film plane will be incorrect so you either have to adjust the height of the waist level GG or adjust the mirror to match the film plane.

If, when you think you have them in agreement, you focus on a plane perpendicular to the camera (e.g. brick wall), you can check mirror alignment. If the brick wall is in focus top to bottom, then the mirror is probably close enough to call it good. However, if either top or bottom edge is out of focus. the mirror is not at the right angle. The top edge would be more easily seen as out of focus since the bottom edge of the mirror would be physically farther out of position than the top edge of the mirror.

 

[wakks]

This means the mirror isn't aligned correctly or the waist level GG needs to be adjusted.




If you can focus at infinity using a GG or tracing paper here, your GG is not at the film plane. You need to have the back on, insert removed to be able to put the GG at the film plane. In these photos, it is directly on the camera body which is a few mm forward of the film plane. Thus, you are unable to focus to infinity where infinity is supposed to be on the helical.


The waist level GG and film plane GG have to agree at infinity. It's not likely that the film plane will be incorrect so you either have to adjust the height of the waist level GG or adjust the mirror to match the film plane.

If, when you think you have them in agreement, you focus on a plane perpendicular to the camera (e.g. brick wall), you can check mirror alignment. If the brick wall is in focus top to bottom, then the mirror is probably close enough to call it good. However, if either top or bottom edge is out of focus. the mirror is not at the right angle. The top edge would be more easily seen as out of focus since the bottom edge of the mirror would be physically farther out of position than the top edge of the mirror.

Same distance I use "frame" from a broken back

 

[cramej]

Same distance I use "frame" from a broken back
View attachment 281625 View attachment 281626

I see that you were focused at infinity in Post 28. What changed from there to 29?

 

[choiliefan]

Your tracing paper is exactly the same plane as the film would be when loaded?
It appears closer to the body in the pics, no?

 

[wakks]

I see that you were focused at infinity in Post 28. What changed from there to 29?

i really don't know what's happening, the bumper fix, the mirror alignment etc... it drives me crazy , I have to get to fix it, because prices of film cameras are crazy right now, but i must admit my limit

 

[wakks]

Your tracing paper is exactly the same plane as the film would be when loaded?
It appears closer to the body in the pics, no?

 

[choiliefan]

Looks good to me.
Is the GG focus screen set properly?
If so, adjusting the mirror to 45 should correct the problem.
Should is the operative word, however.

 

[wakks]

Looks good to me.
Is the GG focus screen set properly?
If so, adjusting the mirror to 45 should correct the problem.
Should is the operative word, however.

i try i try

 

[abruzzi]

resurrecting a an old thread--I recently bought an EC-TL, and everything seems ok functionally, but I just noticed a double image in the viewfinder in the upper portion of the image. The wider the lens, the more prominant the double image. So the 50mm is very noticable and the 150mm, not so much. My first thought is that the lower mirror is probably out of alignment, causing this. @itsdoable posted an image above of an adjustable stop for the mirror, but I cant figure out how to adjust it.

First, anyone with experience, is my diagnosis the likely cause? Second, it is possible to adjust without a major teardown? if it only adjust the lower mirror, I figure I can adjust to align with the main image unless there is a reason that won't work?

 

[campy51]

Place something on the mirror and see if you see a space between the object and the reflection. If you do someone put in a regular mirror and not a front surface mirror. Be careful not to scratch the mirror in case it is the right one.

 

[reddesert]

resurrecting a an old thread--I recently bought an EC-TL, and everything seems ok functionally, but I just noticed a double image in the viewfinder in the upper portion of the image. The wider the lens, the more prominant the double image. So the 50mm is very noticable and the 150mm, not so much. My first thought is that the lower mirror is probably out of alignment, causing this. @itsdoable posted an image above of an adjustable stop for the mirror, but I cant figure out how to adjust it.

First, anyone with experience, is my diagnosis the likely cause? Second, it is possible to adjust without a major teardown? if it only adjust the lower mirror, I figure I can adjust to align with the main image unless there is a reason that won't work?

Yes, a double image or an image that shifts as you pivot the camera up/down and an object moves in/out of the upper area of the field of view is a sign of a misaligned lower mirror.

itsdoable said that the lower mirror stop on the EC-TL is an adjustable screw. I don't have an EC-TL, I have an EC, and apparently the stop mechanism is different.

 

[abruzzi]

yeah, mine doesn't seem to be easily adjustable--hence the question. At first I thought that the first photo @itsdoable posted was an adjustment screw, but it doesn't seem to be, at least on mine. I'm not sure if the glass was replaced, but it definitely looks front silvered.

 

[itsdoable]

Its been a while since I worked on a EC-TL.

Before you adjust anything, check the reflection of some object on the mirrors (ie, the lens mount or focus screen) and check to see if the mirrors are aligned. If the reflection across the mirror looks aligned, then do not adjust the stops. That is my advice.

Also, check that the mirrors are properly mounted in their carriers. Cover the secondary mirror and check the view. Then the primary mirror.

This is what my mirror stops on my EC-TL looks like.

The black metal arm with the flat stop for the main mirror can be adjusted up and down from the other side of the mirror box, you will have to disassemble the camera to get to it. The round screw like thing with the flat head threads in and out to adjust where the secondary mirror stops when it swings up. You grip the head with a special cup-plyer to turn the head (early Hasselblad had similar adjustment screws). Again, easier to do with the camera disassembled. These adjustments are not easily accessible because they do not usually need to be done.

The whole mechanism is spring loaded so when the mirror comes down, the spring, along with the rubber bumper on the other side, can cushion the main mirror's return.

Again, do not adjust it if it does not need it. Make sure everything else is checked first. I've warned you.

Of course someone else may have already done that, which is why it's off...

 

[abruzzi]

thanks for the detail. I wasn't able to test during the week, because I was working from dark to dark, so finally this morning I was able to a little bit of testing.

My subject was a little sapling I planted in my front yard last year. This was perfect becuase with no leaves on it yet, I could position the camera on a tripod with the spindly litle branches in front of a background of a cloudy sky and there would be nothing to distract from the double image. I mounted the 50mm f2.8 lens because it seems more pronounced on wide lenses.

The first think I noticed was that as I focused forward and back the offset of the double image changed. It came close to aligned near infinity (though its hard to say for certain because the brances were about a meter away and at infinity they were mostly blurry blobs. But as I came closer to in focus the double image was clearly separated. I'd hazard a guess of several milimeters.

The next test was to block the lower mirror, which I did with a small piece of paper cut to fit. it was hard to get it into place so it only blocked the lower mirror, and my positioning wasn't perfect, but after doing that the double image was gone, though the upper half was dimmer at that point.

So at this point I'm fairly confident that the lower mirror is out of alignment. I suppose its possible that the upper mirror is wrong and the lower one is correct, and I suppose I should do a proper focus test, but since the adjustment for the upper mirror is much harder to get to, I think at this point I'll try moving the lower mirror to see if I can get the lower mirror to align, and if it stays aligned through the focus range. From the photos, it seems like the best way to adjust would be a pair of small needlenose pliers, maybe the kind that are bent at the tip and use it to grab the stop and turn it. I'll probably want a good way to mark the stop so I can tell how far I've moved it.

As a side note, I keep cleaning dark crumbs out of the inside of the camera. The first thing I found causing it was the foam on the focusing screen hold-down frame. So I cleaned that out are replaced the foam. It also looks like there is a flip up rest for the upper mirror that could use some new foam, but whats there now is not crumbly so I don't think it is the source for the crumbs. Are there any other foam seals inside the camera that I should look at?

 

[choiliefan]

Do the EC cameras have foam under the mirrors like the S2A's?

 

[Patrick Robert James]

Do the EC cameras have foam under the mirrors like the S2A's?

Do you mean under the mirror, or under the focusing screen? No foam under the focusing screen for the EC-TL at least.

 

[abruzzi]

Do you mean under the mirror, or under the focusing screen? No foam under the focusing screen for the EC-TL at least.

yeah on the EC-TL there is foam above the focus screen, on the frame that folds down and holds it in place, but below the screen is hard metal.

As for mirrors, the only foam I found is there is a piece with foam that sits vertically, then when you take a shot it flips up horizontally to act as a landing pad for the mirror. I don't know if the purpose of that foam is to provide a soft landing for the main mirror or to act as a light seal to block light coming in from the viewfinder during picture taking (or both.)

 

[Patrick Robert James]

As for mirrors, the only foam I found is there is a piece with foam that sits vertically, then when you take a shot it flips up horizontally to act as a landing pad for the mirror. I don't know if the purpose of that foam is to provide a soft landing for the main mirror or to act as a light seal to block light coming in from the viewfinder during picture taking (or both.)

Probably both.

I took a look at my EC-TL today because of this thread. Mine had the double image which has been bugging me. Turned out the large mirror was off. I adjusted it by bending the little tab under the mirror out a bit. I wonder if that gradually gets pushed in over time by impacting the stop over and over again. It is real close now. Only a touch off at infinity (moon). I think it needs only a tiny adjustment now. I still need to make a bumper for the other side. I wish someone just sold them. I am not sure the foam actually does much except for a bit of padding at the end of the mirror throw.

I need to recover it too but I've never seen anyone selling leather for the EC-TL. I don't really feel like cutting it myself.

 

[abruzzi]

every one I've seen has leatherette that is shrinking or peeling. I did find a Chinese seller that cutting them:

Bronica EC-TL replacement skin cover pre-cut self-adhesive! | eBay

Find many great new & used options and get the best deals for Bronica EC-TL replacement skin cover pre-cut self-adhesive! at the best online prices at eBay! Free shipping for many products!

www.ebay.com

It won't work for the regular EC and I don't know about the TL II, but it fit mine perfectly. Most of the pieces are actually pretty easy to replace, except the front piece which is tricky to align, and piece that surrounds the crank on the film back which is also a bit of a challange.

 

[Patrick Robert James]

every one I've seen has leatherette that is shrinking or peeling. I did find a Chinese seller that cutting them:

Bronica EC-TL replacement skin cover pre-cut self-adhesive! | eBay

Find many great new & used options and get the best deals for Bronica EC-TL replacement skin cover pre-cut self-adhesive! at the best online prices at eBay! Free shipping for many products!

www.ebay.com

It won't work for the regular EC and I don't know about the TL II, but it fit mine perfectly. Most of the pieces are actually pretty easy to replace, except the front piece which is tricky to align, and piece that surrounds the crank on the film back which is also a bit of a challange.

Thanks Abruzzi.