Canon New FD Rear Lens Cap

I feel pretty stupid asking this, but here goes. How do I mount the rear lens cap on a Canon New FD lens?

I've got a 50/1.4 and a 100/2.8. The 100/2.8 came with a rear lens cap, but it just seems to push in and doesn't turn. In fact, it seems to be manufactured so that it won't turn: it has protrusions that prevent it turning (see below). Since it won't turn, it falls off as soon as your look at it.

I am well aware of the little dance one has to mount FD lenses on an adapter (turn one way to engage the lever and then turn the other way to lock). That's not the problem.

So, am I being stupid? Is this rear lens cap defective or perhaps for older breech-mount FD lenses? Can anyone recommend a mark of rear lens cap that does work with New FD lenses?

Regards,

Alan


The lens cap in question.


The thicker protrusion closer to my fingers prevents the lens cap from turning like an adapter.

I have a very similar looking aftermarket cap mounted on a 50/1.4 SSC and just checked it on a new FD 35/2.8 and it won't turn, so it looks like that style of cap just isn't compatible with new FD lenses.

The genuine Canon new FD cap has only one cutout/notch and a arrow mark on the back which you align with the red dot on the lens itself. It is compatible with both types of FD lens.

The older style genuine Canon FD cap has three cutouts (with thicker & thinner parts either side of each cutout, unlike the new FD which is the same thickness throughout) and can be fitted in any orientation on an older style breechlock FD lens but it won't fit on a new FD lens.

Here's a quick (and nasty) snapshot of the 2 styles of cap; FD on the left and New FD on the right, both genuine Canon items:


Original FD cap (left) is the same as the aftermarket cap shown by the OP. The New FD cap has one 'full' cutout and also has a sort of half-cutout at the 8 o'clock position - it can only be fitted with the arrow mark on the back of the cap aligned with the red dot on the lens.

Any FD cap that looks like the one on the right of the image should fit your lens AOK. Maybe any FD cap with a consistent thickness (no thick/thin parts) would also fit?!

Hope that helps

Alan WF said:

I feel pretty stupid asking this, but here goes. How do I mount the rear lens cap on a Canon New FD lens?

I've got a 50/1.4 and a 100/2.8. The 100/2.8 came with a rear lens cap, but it just seems to push in and doesn't turn. In fact, it seems to be manufactured so that it won't turn: it has protrusions that prevent it turning (see below). Since it won't turn, it falls off as soon as your look at it.

I am well aware of the little dance one has to mount FD lenses on an adapter (turn one way to engage the lever and then turn the other way to lock). That's not the problem.

So, am I being stupid? Is this rear lens cap defective or perhaps for older breech-mount FD lenses? Can anyone recommend a mark of rear lens cap that does work with New FD lenses?

Regards,

Alan

The lens cap in question.

The thicker protrusion closer to my fingers prevents the lens cap from turning like an adapter.

Click to expand...

As you said, you have to push in and turn. Older breech lock caps still works on newer FDn mounts. Yours seems to be defective and i have never seen that little tab before.

I have also never seen that type of cap before. FL, FD and New FD should all be compatible. I have all three. I am guessing its a cheap third party manufacturer and it'll probably be a hassle to get a replacement or return it. I would just shave down the tab with sandpaper until its flush and call it a day.

I'm replying without holding an FDn lens and a cap in my hands, so bear with me. I hope this helps and that I'm not missing the point of your question.

The cap itself doesn't turn - the breech lock does.

• Put the lens fully in open/unlocked position.
• Place the cap on the lens where the pin fits in one of the three notches on the cap.
• Turn the breech to lock position. With the cap that has extra thickness on one side, you'll only be able to do this half-way, but it will keep the cap in place.

UPDATE: Oops, I'm totally wrong. I was using my Sigma 50/2.8 macro as a reference, which I thought used the FDn mount, but it actually uses a hybrid of FD and FDn. Strange.

The FD caps that I generally know have one prominent centre notch in a flange that matches a pin in the lens itself. We all know that the lens mechanism itself should be in a position so that the corresponding pin is centred or it will not fit.

I can see that there are slightly different styles of FD end caps and I have not met the more difficult one luckily.

The FD/FL Breech or FDn mount is a mount where that small degree of masochism that is needed when first encountered tends to go away once the appropriate hand signals are mastered.

Not a truly brilliant effort on Canon's part and acknowledged by them when they sweetly dumped the FL/FD mount system used by their many devoted customers and replaced it with a largely incompatible locked in by electronic control EF version.

Lucky that Canons intransigence over making a professional level mirrorless camera body has been eased by the manufacturers of electronic adapters. One can almost hear the teeth grinding back at Canon HQ right out here in my remote eyre.

In any case my rather nice EF mount lenses now work fine on non-Canon bodies so I will forgive them this time .....

Tom Caldwell said:

The FD caps that I generally know have one prominent centre notch in a flange that matches a pin in the lens itself. We all know that the lens mechanism itself should be in a position so that the corresponding pin is centred or it will not fit.

I can see that there are slightly different styles of FD end caps and I have not met the more difficult one luckily.

Click to expand...

All my breech lock 'old FD' lenses (sourced from various domestic locations and other countries) have the rear cap with thick & thick parts on either side of the notches. I've never bought further afield than the EU so maybe it was a European thing?! I never thought there was anything out of the ordinary about them...

Tom Caldwell said:

The FD/FL Breech or FDn mount is a mount where that small degree of masochism that is needed when first encountered tends to go away once the appropriate hand signals are mastered.

Not a truly brilliant effort on Canon's part and acknowledged by them when they sweetly dumped the FL/FD mount system used by their many devoted customers and replaced it with a largely incompatible locked in by electronic control EF version.

Lucky that Canons intransigence over making a professional level mirrorless camera body has been eased by the manufacturers of electronic adapters. One can almost hear the teeth grinding back at Canon HQ right out here in my remote eyre.

In any case my rather nice EF mount lenses now work fine on non-Canon bodies so I will forgive them this time .....

--
Tom Caldwell

Click to expand...

Alan WF said:

I feel pretty stupid asking this, but here goes. How do I mount the rear lens cap on a Canon New FD lens?

I've got a 50/1.4 and a 100/2.8. The 100/2.8 came with a rear lens cap, but it just seems to push in and doesn't turn. In fact, it seems to be manufactured so that it won't turn: it has protrusions that prevent it turning (see below). Since it won't turn, it falls off as soon as your look at it.

I am well aware of the little dance one has to mount FD lenses on an adapter (turn one way to engage the lever and then turn the other way to lock). That's not the problem.

So, am I being stupid? Is this rear lens cap defective or perhaps for older breech-mount FD lenses? Can anyone recommend a mark of rear lens cap that does work with New FD lenses?

Regards,

Alan

Click to expand...

This lens cap I most likely aftermarket, the 'C' on the back side is a clue.

Alan WF said:

The lens cap in question.

The thicker protrusion closer to my fingers prevents the lens cap from turning like an adapter.

Click to expand...

There are a few caps that are thicker like that, they were intended for breach lock lenses, the reason was to prevent the cap and breach lock ring from becoming stuck because the ring was turned too far/tight.

I would suggest getting the proper nFD cap.

A possible issue can be that the inner part of the nFD mount can be made to unlock and rotate, which makes it impossible to mount.

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Thanks to everyone who replied. Five minutes with a file reduced the profile of one of the larger protrusions, and the cap now turns and locks.

Regards,

Alan

SimonOL said:

Tom Caldwell said:

The FD caps that I generally know have one prominent centre notch in a flange that matches a pin in the lens itself. We all know that the lens mechanism itself should be in a position so that the corresponding pin is centred or it will not fit.

I can see that there are slightly different styles of FD end caps and I have not met the more difficult one luckily.

Click to expand...

All my breech lock 'old FD' lenses (sourced from various domestic locations and other countries) have the rear cap with thick & thick parts on either side of the notches. I've never bought further afield than the EU so maybe it was a European thing?! I never thought there was anything out of the ordinary about them...

Click to expand...

I doubt if it is a European thing Simon and don't doubt for a minute that there was a breech lock version. Just my personal experience has been with the same type of FD cap despite having a mixture of breech and FDn lens mounts. I think I once had the type of cap that is being described here but maybe I (deliberately) lost it in my frustration.

As a "lens collector" I have ceased to be amazed at the number of lenses that are sold minus one cap or both. As a result I have stocked up in a drawer full of cheap spare caps. Maybe my experience has been that the caps I bought in bulk were all of the more recent type?

SimonOL said:

SimonOL said:

The FD/FL Breech or FDn mount is a mount where that small degree of masochism that is needed when first encountered tends to go away once the appropriate hand signals are mastered.

Not a truly brilliant effort on Canon's part and acknowledged by them when they sweetly dumped the FL/FD mount system used by their many devoted customers and replaced it with a largely incompatible locked in by electronic control EF version.

Lucky that Canons intransigence over making a professional level mirrorless camera body has been eased by the manufacturers of electronic adapters. One can almost hear the teeth grinding back at Canon HQ right out here in my remote eyre.

In any case my rather nice EF mount lenses now work fine on non-Canon bodies so I will forgive them this time .....

Click to expand...

Click to expand...

Tom Caldwell said:

I doubt if it is a European thing Simon...

Click to expand...

So do I - I wasn't really being serious ;-) Just a bit surprised so few people seem to have come across this style of cap.

Here's what they look like from the top, just for reference:

http://www.ebay.co.uk/itm/Canon-FD-...271417?hash=item281cc39479:g:V2UAAOSwewJTnCpJ

Tom Caldwell said:

and don't doubt for a minute that there was a breech lock version. Just my personal experience has been with the same type of FD cap despite having a mixture of breech and FDn lens mounts. I think I once had the type of cap that is being described here but maybe I (deliberately) lost it in my frustration.

As a "lens collector" I have ceased to be amazed at the number of lenses that are sold minus one cap or both. As a result I have stocked up in a drawer full of cheap spare caps. Maybe my experience has been that the caps I bought in bulk were all of the more recent type?

--
Tom Caldwell

Click to expand...

Alan WF said:

Thanks to everyone who replied. Five minutes with a file reduced the profile of one of the larger protrusions, and the cap now turns and locks.

Regards,

Alan

Click to expand...

Attaboy, it is good to see applied ingenuity ....

--
Tom Caldwell

Tom Caldwell said:

Alan WF said:

Thanks to everyone who replied. Five minutes with a file reduced the profile of one of the larger protrusions, and the cap now turns and locks.

Click to expand...

Attaboy, it is good to see applied ingenuity ....

Click to expand...

This is right at the limit of both my application and my ingenuity.

Regards,

Alan