Sigma 105 macro Nikon fit. help needed.

[hillwalkinggirl]

I have the above lens, but am just a little confused about a couple of things. I use it mostly in MF and I do this by turning the little AF/MF switch on my D80 to MF. Is there anything else that I am supposed to do? I have just noticed (after wondering why the barrell wasn't moving in and out] that there is a clutch on it which is activated by pulling in an out.

What is the purpose of this. I presume that when I want to AF I just click the switch back on my camera body, but do I also need to disengage this clutch?

Also can any one explain the markings on the barrell 1:1, 1:2, 1:15 etc. What do they actually signify? When shooting very close up I set it to 1:1 and then rock back and forth, but as a comparison what would I be shooting with the setting on MF 1:15.

Any help would be appreciated please, as the bit of paper which called itself a manual with the lens was not very helpful, and I couldn't decide which bit applied to the Canon fit and which bit applied to the Nikon fit.

 

[dinorock]

hi hwg the markings on your barrel are the acual magnification as a fraction 1:1 means what your shooting is real life size on your sensor 1:2 is half size and so on hope this helps not sure about the clutch i read some where you can manual focus on some lenses without changing to mf dont force it unless your sure i may be wrong maybe some one else can help with this one:shrug:

 

[stan the man]

barbara,you have to move the ring on the front of the lens back and forth.also as you know,i don't have mine at present,but i'm sure if you pull the ring back,you will be able to use manual focus

also..as dinorock has said,the 1:1,1:2 markings are the image size your shooting at,with 1:1 being true macro

 

[hillwalkinggirl]

hi hwg the markings on your barrel are the acual magnification as a fraction 1:1 means what your shooting is real life size on your sensor 1:2 is half size and so on hope this helps not sure about the clutch i read some where you can manual focus on some lenses without changing to mf dont force it unless your sure i may be wrong maybe some one else can help with this one:shrug:

Thanks dinorock. I thought that's maybe what they were, but my brain is trying to convert it to distance from the subject. I'm trying to work out that if I engage the clutch on the lens to AF do I have to change the setting on the camera as well, and vice versa for MF. Or does the clutch do the trick in both cases. Anyone help on this please.

 

[Nod]

The 1:1, 1:2 etc markings are the ratio of the actual size of the subject to the size of the image that's projected on the sensor, so at 1:1 on a Dx sensor (23.7mm x 15.6mm) a subject the size of a normal postage stamp will fill the frame and even overlap a little. Rocking back and forth at such a close distance will make accurate focus quite hard since the depth of field (even at small apertures) is miniscule!

Not sure about the push/pull clutch on the Sigma - but on the D200, using a Tamron 90mm (same sort of push/pull mechanism) the body and the lens must BOTH be set to MF. If the body's set to AF but the lens is set to MF, the focus ring will be rotated by the AF motor, putting extra strain on the motor, especially if there's anything touching it or holding it...

 

[hillwalkinggirl]

barbara,you have to move the ring on the front of the lens back and forth.also as you know,i don't have mine at present,but i'm sure if you pull the ring back,you will be able to use manual focus

also..as dinorock has said,the 1:1,1:2 markings are the image size your shooting at,with 1:1 being true macro

Thanks Mark, but what has confused me is that the Nikon fit seems to be different from the Sony and Canon. From what I can see they also have a switch on the lens. Sigma are very confusing as they put it all in one paragraph and I'm not sure whether they are referring to all instances or just the one type of camera.

 

[stan the man]

Thanks Mark, but what has confused me is that the Nikon fit seems to be different from the Sony and Canon. From what I can see they also have a switch on the lens. Sigma are very confusing as they put it all in one paragraph and I'm not sure whether they are referring to all instances or just the one type of camera.

the only switch on my 105 is a limiter switch,which gives you the option of having full or limited AF,which reduces the amount of hunting the lens will do to find focus..

 

[Werecow]

I think the nikon fit version of this lens doesn't need the auto/manual switch because its on the camera body anyway?
I was a bit confused about the push pull element too when i first got this lens. It's basically just to stop the focus barrel rotating with the motor when it's in AF mode (can actually hold it properly then!).
The limiter switch will limit the lens to close focussing or far focussing depending on where the lens barrel is when you push the switch.

 

[hillwalkinggirl]

Thank you all - sorted at last thanks to all your helpful input. I just wish some of these companies would learn to write manuals in sensible English.