Nice work people. This gets me excited over the 58/1.2 once again.
Phillip, how did/do you go about when it comes to infinity? I've been on my way to grind my retainer ring for many months now. Finally last week when I meant to screw it off to grind the ring in safe distance from the lens. But found it seem like a full section of rear glass group will be screwed off. So I stopped as I am very novice at lens surgery. Now I am leaning towards dremel it on the lens with a lot of tape instead.
wfrank wrote:
Phillip, how did/do you go about when it comes to infinity? I've been on my way to grind my retainer ring for many months now. Finally last week when I meant to screw it off to grind the ring in safe distance from the lens. But found it seem like a full section of rear glass group will be screwed off. So I stopped as I am very novice at lens surgery. Now I am leaning towards dremel it on the lens with a lot of tape instead.
I grinded down the retainer ring myself, and it is rather easy if you unscrew the rear lens group like you did. I then placed a sanding paper flat down on a table and with the lens group held at an angle to keep the rear lens from touching the sanding paper, it was easy to sand down the retainer ring without harming the rear element. Still canīt focus to infinity though, but I think my 5DMkII has less clearance than average.
It is common knowledge (or was, anyway - somehow it seems to be forgotten) that the vast majority of 5Dc and 5DII mirrors will still collide with the Rokkor, even after the rear element retaining ring has been reduced. A FEW of these cameras have a large enough tolerance that a FEW people have reported that reducing the Rokkor RERR was enough.
The mirror mod is far easier than people think it is, and it enables the camera to accept much more than a modded Rokkor...
Bifurcator wrote:
What does it entail specifically? A high-speed grinder? mirror removal? Write out the steps or link it us up to a tute that's sane.
Disclaimer: If you lack common sense and/or handy-eye coordination, don't even begin this project. I take no responsibility for any loss or damages incurred by someone who performs this procedure. Having said that, if you are a "handy" type of person (ie. your wife doesn't have to hang pictures and install light fixtures for you) then you can probably do this quite safely. If I can do it half drunk...
Materials/Tools list:
- 2" wide masking tape (the good, sticky kind, not that stuff that peels off too easily)
- variable speed drill
- grinding stone (or 2 or 3, as they can get clogged)
- vacuum cleaner with hose attachment
- safety glasses
- dust mask
Procedure:
1) Use masking tape to lift and hold mirror in a semi-swung position close to the mouth of the camera. Ensure that the tape is stuck completely and leave NO GAPS AT ALL. (Yes, I am YELLING).
2) Use many more strategically placed pieces of masking tape to surround and seal the mirror (leave exposed the edge of the mirror to be removed) and COMPLETELY SEAL OFF THE MOUTH OF THE CAMERA. How much mirror you grind off is completely up to you, but between 1 and 2 mm is a good ballpark.
3) Repeat step 2) building layers of masking with the goal of making it completely impermeable - it does double duty as a very secure means of holding the mirror completely stationary during the grinding process. This is BY FAR THE MOST IMPORTANT STEP (Yes, still yelling).
4) Attach the grinding stone to the variable speed drill, adjust the speed to low RPM (high speed will increase all associated risks and has no benefit other than time - if you don't have the time to do this right, don't do it at all). I do not recommend the use of a Dremel or other such high-speed device.
5) Arrange the vacuum cleaner close enough that you can tape the nozzle of the hose as close to the camera mouth as possible, or otherwise secure it in such a way that the bulk of the dust/debris will immediately be sucked into the vacuum.
6) Put your mask and safety glasses on, turn on the vacuum cleaner, then proceed to grind the edge of the mirror, ensuring that the rotation of the grinding stone is in-line with the length of the edge. In other words, do not grind across the edge or you will risk chipping or other mirror/camera damage. Regulate pressure on the grinding stone such that it removes material but does not put excessive force on the mirror. The tape will hold it very well (if you did 2 and 3 above right) but unreasonable pressure will result in disaster.
7) Check your work often.
8) When the mirror has been reduced sufficiently, use the vacuum to clean the mouth area completely (perhaps a dry paint brush would be handy here) and then slowly and carefully remove all the masking tape. Try to hold the camera in such a way that any remaining particles fall away from the mouth during this step.
9) Inspect the mirror chamber, shutter blades, etc. for signs of dust/debris. If you did steps 2 and 3 correctly, there should be no dust/debris whatsoever.
10) Enjoy your mirror-modded camera.
* Optional. Drink 3 strong gin & tonics (or other favourite drink) before beginning
BTW, I am planning to modify my other 5Dc mirror at some point and when I do I will take photos and/or video to document the process. So, if you are patient and feel you might benefit from photos/video, then wait a while.
hmm, some serious work there. Might have to pass on it as don't have the space to do such a job. Shame as my 35 1.4 is taking a beating from the mirror so I might just have to adjust infinity back a bit so it can never contact.
Seems simple enough! What grit of stone is optimal in your opinion?
BTW if indeed a person chooses to use a dremel check OFTEN the temperature of the mirror and don't apply much pressure! Jelly heat syncs can work here as well. As most will know it's temperature unevenness which so easily can crack or break glass! Applying significant pressure from a high-speed stone can turn a small (uneven) area of glass red-hot in under 2 or 3 seconds! I've made this mistake while working on glass with a dremel at only about 5,000rpm. It wasn't a camera mirror tho...
BTW if indeed a person chooses to use a dremel check OFTEN the temperature of the mirror and don't apply much pressure! As most will know it's temperature unevenness which so easily can crack or break glass! Applying significant pressure from a high-speed stone can turn a small (uneven) area of glass red-hot in under 2 or 3 seconds! I've made this mistake while working on glass with a dremel at only about 5,000rpm. It wasn't a camera mirror tho...
I run about 1200rpm when mirror-modding.
Looking forward to the pictorial cogitech!
Thanks again!
It could be a while. Probably in the new year... Hopefully before spring.
I've never attempted to remove the mirror, but the consensus at the time (a few years back) was that it is not supposed to be removable. Of course, they do fall off the odd 5D but as long as mine is stuck on there well, I'd rather not mess with it (other than the shave! )
sebboh wrote:
... is the mirror that difficult to remove? seems like it would be a lot easier to just take it out and trim it?
There was an early batch of 5D's that had faulty bonding of the mirror to the frame and there were cases where the mirror fell out. They improved the bonding process.
If the mirror was removed for grinding or one wanted to re-glue a loose mirror, care should be taken because if the mirror is shifted the slightest bit by a layer of adhesive, that would change the viewfinder focus calibration, which would require a re-calibration using the viewfinder shims.
If the mirror falls out and needs to be replaced, Canon only sells the 5D mirror as a mirror assembly, for about $200, plus labor.
Do it! It's a relatively simple job, once you have it back together anyway! My aperture blades collapsed last time I took my rokkor apart for cleaning, took a while to it back together but I'd be able to do it much quicker next time
)