Canon Sales and Service Center. Soft drawstring lens case made for Canon EF 135mm f/2.0L, EF 24-70mm f/2.8, EF 28-70mm f/2.8L, EF 100mm f/2.8 USM, EF. Old, Inexpensive, and Tack-Sharp: Canon’s Best Lenses You Don’t Know About. 28–70 f/3.5–4.5 II. The Canon 28–70mm f/2.8 II. This lens is a beast. Don’t let its humble design. #8156 - Canon EF 70-210mm F4 Lens Service & Repair Manual. Detailed illustrated service and repair instructions, schematics, parts listing. 18 pages, $15.00. Jan 07, 2015 Service Manual English Edition. EF 50mm 1:1.8 EF 28mm 1:2.8 EF 15mm 1:2.8. Electrical Diagrams. It is copyrighted by Canon 1987. In any case, this document contains a wealth of information. I have not gone through it entirely to find all of the points pertinent to these discussions. Disassembling Canon EF 35-105mm F4.5-5.6 Lens. Back Canon EF 35-105mm F4.5-5.6 Repair; Full Screen. It's a good idea to switch the lens to manual at this.
Introduction
This guide shows how to disassemble a complicated (but cheap) SLR lens, and hopefully reassemble it in working order. Please note that this is a fiddly and complicated procedure; if you value your lens and definitely need it to work, service it. I purchased an 'untested' camera from eBay that had obviously been drop tested.
First, remove the two screws in the barrel of the lens with a philips 0 screwdriver
Next, remove the four screws holding the rear cover of the lens on
Remove the rear cover, and then remove the rubber seal (shown in place around the edge of the lens in this picture).
Note the piece of plastic that just fell out. Not a good sign!
Gently lift and remove the plastic barrel next to the focus switch. My one was already cracked.
Gently manipulate and remove the AF/M focus switch - it is held in by four easily breakable brittle plastic clips.
Watch out for the autofocus mechanism and control wires. They are very delicate.
It's a good idea to switch the lens to manual at this point - adjusting the focus can help when removing the autofocus motor
Remove the top two control wires by releasing the clamps, and then gently easing the wires from the connectors
Do not remove them by pulling the sticking out plastic parts (one is obscured by my finger here) - these will tear off
Gently lever the control board out from under the plastic tabs
Mind the cable underneath the board
Make sure you don't touch the lens element in the centre!
Lift up the board, and then gently pull the lower connector out by the solid connector
Then, remove the control board entirely
Next, we will remove the autofocus mechanism
Remove the two screws shown
Be careful with the control cables. They tear easily. The aperture control cable on this lens is damaged already.
Lift off the focusing mechanism.
It's best to have the focusing mechanism in manual (M) - then extending the lens will help you remove the mechanism
Remove the ringed screw and lift out the metal guide.
Remove the screws holding the rear element and aperture in place.
Gently turn the zoom so it is nearly at 35mm
This will lift the rear element and aperture unit towards the rear of the lens, and align the three legs with gaps
Lift the rear element and aperture unit out
Gently rotate the aperture unit anti-clockwise so that the three ringed legs no longer lock it in place.
On my lens, there was one of the three legs intact, and the aperture unit was hanging off uselessly.
If your aperture unit is like mine, apply superglue around the outer rim, and replace
Don't get any on the glass!
That's as far as I went - the zoom was no longer jammed, and reassembly was the best option here! Reassembly is the reverse of disassembly
The aperture unit/rear element is slightly tricky to put back. Make sure you align it correctly (lens nearly at 35 mm, so that the screw holes are high up).
Remember to blow dust out of the lens if you see any as you are reassembling it. Do not use anything liquid to clean the inside of the lens unless you know what you are doing.
Put the random bits of plastic in your man (or woman) drawer. Who knows when they will come in handy?? But seriously, here's what I found:
That slightly torn aperture cable did not affect operation of the lens. It works perfectly.
Completely reassemble the lens and test on your SLR/D-SLR. Now you can take badly exposed shaky indoor shots like the one shown again!
Don't think you can get away without those tiny screws in the barrel. They hold the contacts in place. I tried and focusing did not work!
Canon Ef Lens List
Complete disassembly and some super glue fixed my lens, but not everyone will be so lucky.
Complete disassembly and some super glue fixed my lens, but not everyone will be so lucky.
10 other people completed this guide.
Canon 28 70mm Lens
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