What is a trim ring?

[Bike Tourist]

I was looking at a used Leica Elmarit-M 28mm f/2.8 ASPH advertised as complete except no trim ring. What is it exactly and is it necessary?

Thanks.

 

[Larry H-L]

Not certain on this particular lens, but some lenses have a trim ring to cover and protect the lens hood attachment points, when a hood is not being used. And it looks better when a hood is not used.

 

[Robert Lai]

He either means the ring at the front of the lens that is threaded to hold filters, or the ring around the front element that identifies the lens. The ring at the front that is threaded to hold the filters on many lenses also holds the front identification disk/doughnut.



If you're missing the lens ID ring, then you don't have a serial number for the lens. Without the other ring, you can't mount filters.


The deeper question is - why is it missing?
If it's a lens that is the victim of a botched up home repair attempt, then you're better off looking elsewhere.

 

[madNbad]

Leica redesigned both the 28 2.8 ASPH and the 35 2.0 ASPH with a new hood similar to the Voigtlander design. Instead of the previous snap on hoods, there are threads around the outside of the lens the hood screws onto. The ring is to both protect the threads and give a finished look to the lens if the hood is not attached. Occasionally a user will remove the ring and attach the hood, then forget where they put the ring when they decide to sell the lens. You can always order a new ring from Leica.

 

[Roger Hicks]

He either means the ring at the front of the lens that is threaded to hold filters, or the ring around the front element that identifies the lens. The ring at the front that is threaded to hold the filters on many lenses also holds the front identification disk/doughnut.



If you're missing the lens ID ring, then you don't have a serial number for the lens. Without the other ring, you can't mount filters.


The deeper question is - why is it missing?
If it's a lens that is the victim of a botched up home repair attempt, then you're better off looking elsewhere.

Dear Robert,

The highlighted portion is my understanding of the normal use of "trim ring" -- and I wholeheartedly agree with the last part of your post. But of course the "bump ring" on some lenses could be called the same thing.

Cheers,

R.

 

[Bike Tourist]

Leica redesigned both the 28 2.8 ASPH and the 35 2.0 ASPH with a new hood similar to the Voigtlander design. Instead of the previous snap on hoods, there are threads around the outside of the lens the hood screws onto. The ring is to both protect the threads and give a finished look to the lens if the hood is not attached. Occasionally a user will remove the ring and attach the hood, then forget where they put the ring when they decide to sell the lens. You can always order a new ring from Leica.

Thanks for your input everybody. This explanation seems plausible. I guess I can give the seller a call to find out for sure.

 

[Gregm61]

That's definitely it. The last two M lenses I purchased new, the 35mm f1.4 FLE and the 21mm f3.4 Super Elmar, on opening the box the hoods were mounted on the lens and the hood caps were on.

The trim rings are contained in cut-outs underneath the lenses in the leather pouches, underneath the regular lens caps you use if you choose to un-mount and not use the hood.

The new, current version lenses that use the updated metal hoods that are notched to screw on and lock in perfect alignment are all packaged that way. The ones I have first-hand experience from either handling in-person or purchasing are the 28 Summicron and Elmarit, the 35 Summicron and Summilux, 21mm Super Elmar, 18mm Super Elmar and 24mm f3.8 Elmar.

I''ll second Larry's comment about the 35mm f1.4 FLE looking better without the hood. I use the Summilux FLE more with the hood on than off more to protect the front element from being banged and my own sometimes fumble fingers than to protect the front element from the sun as the lens seems to work the same against the light with or without the hood, but having it off the viewfinder is much less blocked in the lower-right, and the "look" is much nicer in my opinion, and I am very careful about returning the ring to the case/box so it does not become lost. I've not checked into the cost of needing to replace it, but it's probably not hard or incorrect predicting it would be a very expensive ring to have to buy separately.