Dralowid
Michael
If you have the good fortune to have one of the big 400 or 560mm Telyts with 'follow focus' ie slide focussing you may be annoyed by a jerky movement and assume that you need to pull the thing apart and lubricate the three steel rods that act as bearings.
Before you do, have a look at the little roller underneath...see poor pic...
IMG_2463 by dralowid, on Flickr
Despite its size this little roller has a big job to play supporting the heavy lens head and allowing the focus action to slide. I had assumed that the two little screws just visible were simply retaining screws...but they are not. They adjust the height of the axle on which the little wheel runs and therefore adjust how much of the lens head's weight is carried by the roller.
I reckon the adjustment is correct when supporting the lens head no longer has an effect on the smoothness of the focus slide.
If you haven't one of these lenses this won't make any sense at all, if you have one it may help.
next...the Lecaflex Motor!
Michael
Before you do, have a look at the little roller underneath...see poor pic...
IMG_2463 by dralowid, on FlickrDespite its size this little roller has a big job to play supporting the heavy lens head and allowing the focus action to slide. I had assumed that the two little screws just visible were simply retaining screws...but they are not. They adjust the height of the axle on which the little wheel runs and therefore adjust how much of the lens head's weight is carried by the roller.
I reckon the adjustment is correct when supporting the lens head no longer has an effect on the smoothness of the focus slide.
If you haven't one of these lenses this won't make any sense at all, if you have one it may help.
next...the Lecaflex Motor!
Michael
Ronald M
Veteran
:bang:Thanks.
Ronald M
Veteran
Thanks you interesting:bang:
Dralowid
Michael
So, Ronald, do you admit to the same mistake as me? Hours of careful disassembly, cleaning and lubrication that didn't make that much difference?
uhoh7
Veteran
My 400/5.6 has been getting stiff so this may help. Any advice on if/and/or/what to lubricate the little roller.
Do you guys notice a big field curvature at 5.6? Mine is huge shooting with A7.mod digital.
Do you guys notice a big field curvature at 5.6? Mine is huge shooting with A7.mod digital.
Dralowid
Michael
Check that the roller is running already, if it is I'd either not lubricate or use at most just a tiny drop of light oil.
When checking whether it moves make sure it is making contact with the lens when the weight it is on it.
Mine's a 6.8 560. I think all the lenses in this achromat family have a well documented reputation for field curvature but since I use mine for wildlife etc I don't notice it. Tack sharp though.
When checking whether it moves make sure it is making contact with the lens when the weight it is on it.
Mine's a 6.8 560. I think all the lenses in this achromat family have a well documented reputation for field curvature but since I use mine for wildlife etc I don't notice it. Tack sharp though.
Shac
Well-known
Thanks Michael - most useful info
David
David
Shac
Well-known
Michael - just got round to checking my 400/6.8 - but no roller visible. Was yours a 560/6.8?
Dralowid
Michael
Mine's a 560/6.8...haven't got the 400.
Looking at a picture of the two lenses together I can see that there are far more differences than I had remembered and furthermore the 560 is almost half a kilo heavier...
Apologies...
Looking at a picture of the two lenses together I can see that there are far more differences than I had remembered and furthermore the 560 is almost half a kilo heavier...
Apologies...