Distagon 4/40 CF T* - Mystery front ring question

[bharat_mistry]

I recently purchased a used CF 40mm off ebay. I didn't receive any

documentation and couldn't find a manual on the Hassey site. The

lense is in great shape and the test pics came out fine.

 

The focus, aperture and shutter rings move smoothly without problems.

The DOF works fine aswell.

 

Just have a question regarding the markings on the front ring, just

behind the hood. From left to right, there is the infinity symbol, 2,

0,9 and 0,5m marking with a bar at each number. The ring in front is

set at the 0,5m mark. Is this ring supposed to move? I can't budge it

to the other marks (don't want to force anything either). What is the

purpose of these markings and function of the ring. How do I adjust

the settings for this? My 80 and 180 lenses dont have it, so I'm just

a bit perplexed. I'm assuming it only appears on the ultra wide

lenses.

Thanks in advance, BM.

[nicholas_t.]

Sounds like a floating element ring. You put it to the distance which the lens is being used at and I presume return it to infinity when finished. I dont know how to move these rings.

[huib_smeets]

Bharat,

 

It is a FLE design, Floating Lens Element. One of the lens elements can be adjusted to give better sharpness at the marked distance on that ring. The idea is to improve lens performance in nearby distance focussing. First set the FLE ring and than focus, the other way around is wrong, or at least you need to refocus. FLE design is used for the 40 and 50mm wide-angle lenses.

 

Huib

 

www.huibsmeets.com

[terry_dent1]

Thes FLE rings are supposed to turn easily but sometimes bind up, probably from lack of use. The ring on my 40mm CFE did this. I was finally able to power it loose. It did take some effort though. Once free it has worked well since.

[bharat_mistry]

Thanks for the quick insight guys. Appreciate it.

 

Should that ring turn as easily as the other - just left and right or is there some sequence of maneuvers that I need to try. On or off the camera, it won't budge.

[r_miller1]

The ring in front should move between the end marks, with distinct detents at the three marks. It should require a firm pressure to move it. The function is to provide optimal lens performance in the indicated focus ranges . When focused between infinity and 2 meters, the ring should be set the mark on the left, and so on.

 

As stated, a firm pressure is required, i.e., substantially more effort than say the focus or aperture rings.

 

You are right, the 40, and I think one of the 50's were the only ones - the provision was made to permit better performance at close focusing distances.

 

Best of luck.

[bharat_mistry]

Thanks guys.

 

Doesn't seem to want to budge when I try to turn it. I tried pulling/pushing on the ring while trying to turn it aswell, no go. Looks like I'll have to find a local repair shop.

 

How much of an improvement in focus/sharpness can I expect by adjust the FLE ring? The lense works fine as is, but if the picture clarity can be improved, I'm all for it. Just hope the repair estimate is worthwile.

 

Later, BM

[jay_.]

<<Doesn't seem to want to budge when I try to turn it. I tried pulling/pushing on the ring while trying to turn it aswell, no go. Looks like I'll have to find a local repair shop.>>

 

Be sure to leave positive feedback for the eBay seller ;>)

[arthuryeo]

<i>How much of an improvement in focus/sharpness can I expect by adjust the FLE ring? The lense works fine as is, but if the picture clarity can be improved, I'm all for it. Just hope the repair estimate is worthwile. </i>

<br><br>

The FLE feature was added to allow you to focus close. If you intend to use it, you need to set it first <b>before</b> you focus, not after. Look up Ernst Wildi's <i>Lenses</i> or <i>Medium Format Advantage</i> books, he explained this concept in detail.