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07-30-2010, 12:43 AM   #1
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lens clamp

I have googled this on this forum and in general and not got a great answer...

what does the clamp do on the FA 100 Macro lens?

Thanks

07-30-2010, 01:13 AM   #2
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It is an detent or arrest clamp to fix the chosen magnification ratio. When ON, you cannot turn the focus ring and the lens reports itself to the camera as manual focus.
07-30-2010, 01:15 AM   #3
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ok why would you want this vs actually being in manual focus? Sorry... seems silly.... personally I just want to know?
07-30-2010, 05:29 AM - 2 Likes   #4
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There are two things here. there is a focus lock switch used to fix the focus...

then there is the clamp, which is a rotating switch. The clamp is used to increase friction on the focus mechanism, to make manual focus more comfortable. It is NOT a lock, as you will see if you try it. It is there because when it isn't MF feels lifeless. Leaving it on when using AF will make AF slower and might, on the long run, damage the AF mechanism.

07-30-2010, 06:44 AM - 1 Like   #5
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QuoteOriginally posted by bdery Quote
There are two things here. there is a focus lock switch used to fix the focus...

then there is the clamp, which is a rotating switch. The clamp is used to increase friction on the focus mechanism, to make manual focus more comfortable. It is NOT a lock, as you will see if you try it. It is there because when it isn't MF feels lifeless. Leaving it on when using AF will make AF slower and might, on the long run, damage the AF mechanism.
I see, my answer was referring to the clamp on the DFA series lens. Interesting to know that the clamp on FA and DFA is a different thing.
07-30-2010, 02:23 PM   #6
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Thanks guys... rep added...
07-30-2010, 03:19 PM - 5 Likes   #7
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QuoteOriginally posted by bdery Quote
There are two things here. there is a focus lock switch used to fix the focus...

then there is the clamp, which is a rotating switch. The clamp is used to increase friction on the focus mechanism, to make manual focus more comfortable. It is NOT a lock, as you will see if you try it. It is there because when it isn't MF feels lifeless. Leaving it on when using AF will make AF slower and might, on the long run, damage the AF mechanism.
Have to say your explanation about the Clamp Screw is somewhat incorrect as the intention is not to adjust the feel of the focusing ring.
Owned the FA 100mm Macro & FA 50mm Macro and the DFA 100mm Macro and DFA 50mm Macro lenses, so allow me to elaborate.

Focus Range Limiter
On the FA & F 100mm f/2.8 Macro lenses, there is a circular switch to focus range limiter switch. On the F version, it has 2 positions (Full/Limit). On the FA version, it has 3 positions (Full/Limit/MF). Full = Full AF throughout from minimum focusing distance to infinity, Manual (MF) = AF is disengaged, full manual focus from minimum focusing distance to infinity,

As the name suggests, the limiter controls the focusing ranges to adjust AF quicker. When the focusing ring is first set at infinity and the switch set to Limit, the AF is set to long distance range (approx 0.6m ~ infinity). If the focus ring is first set to the minimum distance and the switch set to Limit, the AF is set to short distance range (0.3m 1x ~ 0.57m 1/4x magnification). Basically the lens is set up so that will not hunt throughout the entire focusing range. The focus range limiter is not as fast to use and superceded by Quick Shift on the DFA/DA lenses.

Clamp Screw
On the FA 50mm f/2.8 Macro & FA 100mm f/2.8 Macro it is a circular knob. On the DFA 50mm f/2.8 Macro & DFA 100mm f/2.8 Macro, it is a sliding switch. When engaged to the On position, it acts as a friction knob to tighten the focusing ring on the FA lenses, but for the DFA lenses it acts as a lock. Used for copying work on a copy stand or when it is pointing down where the weight of the lens might shift the focus ring. Can also be used to lock to a certain magnification. When shooting in AF mode, the clamp switch should be set to the Off position or it will slow down the AF focusing speed.

Last edited by creampuff; 07-30-2010 at 03:25 PM.
11-09-2010, 02:14 PM   #8
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awesome info, I just got the D FA 50mm Macro and since I bought it used, it didn't have the manual. Thanks for the explanation Creampuff.

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