Filter fittings

[jim_gardner4]

I have just bought a new 503cw with Planar lens. To protect the glass on my

new lens I also got a Hasselblad uv filter that has the bayonet fitting (you

know where Im going with this already). I also use Lee filters and have all

sorts of their threaded ring adaptors for different lenses so I brought a Lee

filter "Hass 60" ring for my new lens. Ok so here is the problem(s). 1.The uv

filter is a smooth fit but will never snap into place so whenever I take the

lens cap of it takes the uv filter off as well. 2.The lee filter/Hass 60

adaptor ring I brought only turns very slightly onto the uv filter before

becoming solid, then when I take it off it takes the uv off as well and its

then a struggle to seperate the two off them. I tried the Lee/Hass 60 directly

on to the lens but that was even tighter. I rang the shop and they sent a new

one straight out to me. The new one is even worse, there is no wey I can turn

it more than a couple of mm on to either the Hasselblad uv or directly on to

the lens. 3.The Hasselblad uv has a small silver pin going through the outer

ring next to the glass. It runs in the same direction the camera is pointing

i.e along the lens direction, not across it. What is it for? As it lines up

just past one of the bayonet clips when the filter is on, I could see that if

it was a screw it would be a very effective way to secure the uv onto the lens

but as its a pin, if it were pushed through, there would be no way of pulling

it back again to ever get the filter off. I have examined the lens the adaptor

and the uv at length and am sure there is no way the uv can snap into place so

it doesnt come off with the adaptor or lens cap. Does any one else use this

set up or have any suggestions?

[ken_wayne1]

Take the little bayonet flanges on the bottom of the filter and gently.....gently bend them out some. It helps the filter to be tighter on the lens. Be very careful, however, not to bend them to fast or too much or else they can break off.

 

Let us know if that helps.

[paul_gardener]

New bayonets need to wear a little.

At the other end of the scale a much used or worn bayonet will not hold a filter/lenscap. It will just fall from the lens.

 

I have a new 80 CFE lens. Normally when the lenscap is fitted correctly the bar with Hasselblad in the cap is exactly horizontal.

To achieve this with a new lens it has to be turned really tight.

 

I know its not normal but is just the way Carl Zeiss makes things.

Older series lenses have a bayonet ring made from alloy.

With CB/CFE/CFi lenses the ring is plastic.

Good thing the rub off of black anodised surface is no longer there.

Less good the fitting of parts to the lens is not as acurate.

[andrew booth]

Jim. This may be an exciting problem, but 16 exclamation marks is excessive. Please temper

your enthusiasm!

[q.g._de_bakker]

Paul,<br><br>I find the fit of the plastic lens cap is a matter of it, not the lens' bayonet, needing to wear in at first, and to have worn out too much eventually.<br>New lens with 'seasoned' cap: no problem. New cap with old lens: too tight to fit properly.<br>Rather annoying when a cap is worn out so much it falls off too easily. Unless forced on, the new replacement cap wil not seat properly and fall off for a while too!<br>So i try to 'help' things along by scraping the cap with a sharp knife in the right places. But luckily, i do not need new caps often. ;-)

[q.g._de_bakker]

Jim,<br><br>The little pin is the stop, so that when filters are stacked, they have something preventing them from turning too far and coming off/loose again.

[paul_gardener]

@ Q.G.

 

For your information I did some research on this subject:

The same lenscap that fails to lock properly on a worn frontring of a lens will not seat as usual on a new CFE lens.

Even with a well used lenscap the bar with Hasselblad on it will not easily reach the horizontal position on new CFE lenses of which I have several.

[q.g._de_bakker]

Paul,<br><br>So it's a complex issue, with both the filter bayonet and the cap playing a role.<br>Sounds like how Leica (used to?) matches the parts of the focussing helicoids of their lenses: finish the threads on both parts finely, though not quite completely, and then 'wear them in' against each other, to achieve a perfect fit.

[jim_gardner4]

Thanks so far. Ok I now know what the silver pin is for but am faced with the horrible possibility of having to tape the uv filter on. If I dont do this the lens cap would have to be extremly loose before it becomes a more free fit than the uv. Also if I do manage to get a Lee filter holder that will go on the front of the uv, it is bound to be tighter than the uv to lens fit resulting in exactly the same problem. Seems to me to be a classic case of over enginnering when a normal thread would have done a better job. Shame. Andrew, point taken (but it was frustration rather than excitment).

[dave_wilson1]

Take this for what it's worth, but I have been doing this for years and it works great. Buy a few Hasselblad (made by Hasselblad) bayonet to 67mm adapters, they're not cheap if new, use the 67 stuff instead of the crap bayonet imitations, everything will work WAY better and you'll be a lot happier.

[ken_wayne1]

To clarify, this is about making it so that you can get off the lens cap without taking off the filter as well correct? They're basically sticking together when you try to remove them?

 

Unless you want to go with Dave's suggestion I would, again, suggest that you bend out the flanges on the bottom of the UV in order to cause the UV to stay tighter on the lens. That way it will hold on the lens as you're trying to remove the cap.

 

The other thing I would suggest is for you to take some sort of tool....turn the cap upside down and pry open the little flanges on the cap that seat in with the UV. I have had caps that were too loose and I will take those little plastic flanges on the back and press them against a table or something which bends them closed a little bit. It's hard but you have to press on it fairly well and they'll then fit snuggly onto the lens. If you do the opposite by prying them open a little then it may free up the tightness of the cap a bit so that it can be removed easily yet still fit snuggly.

 

I've also seen people use just a touch of rubber cement on the flanges of the UV filter in order to hold it in place a little bit but I'd try the other way first. I have several 250mm CFi lenses right now where the owner had put too much glue to do this very thing and now it's going to take a bit of work for me to get them off.

 

Let us know once you get it resolved and what you did.

[paul_gardener]

Q.G.

 

It does not seem complex to me. It is just a nuissance that tolerances and wear are issues that will either result in not fitting or losing a lenscap.

This seems to be more of a problem with later plastic frontrings.

Although I had a 120CF with a worn alloy frontring.

It comes under the price we pay for progress.

[jim_gardner4]

Ken, thats part of the problem while the other part is why 2 brand new Lee filter ring adaptors made for that size lens wont fit? The plastic lens cap doesnt have bendable flanges, they are solid and moulded with the cap.

I have now bent the flanges on the uv to the point of them only just fitting into the lens diameter. Still loose. I then put a very thin piece of gaffer tape (1mm wide and 20ish mm long) along the uv flanges to increase the pressure on the filter/lens fit. That helped a lot but I still needed to put an inch of tape over the filter ring and lens joint on the bottom. For an outfit that costs several thousand pounds, I think having to put gaffer tape on it is really poor.

[q.g._de_bakker]

Paul,<br><br>"Complex", as in "not one single cause". If it is not just wear of the lenscap, but also of ... ;-)<br>Anyhow, i treat caps as 'consumables', just like magazine light traps (and dark slides - though in all the years i use Hasselblads, i never lost or needed to replace one of those). When a cap doesn't seat properly, i do not let it annoy me much, but get a new one.<br><br>Jim,<br><br>The direction to bend the bayonet in is not outward/radial. You need to push the 'flanges' (what is the correct term for these bayonet thingies?) towards the ring of the filter, making the gap between the 'flange' and the ring narrower.