couple of questions re my sigma 105 macro

[gorman81]

I know that this has been mentioned in another thread but I don't believe it was fully answered - Sigma state that both the camera and the lens be set to mf but this is not, in practise, necessary - just setting the lens to mf works and it is therefore very quick to change from mf to af but does this cause any damage internally or electronically in the 510 body?
Also - why does the focussing ring move forwards/backwards? I must have moved this by accident when I put the camera away and when I came to use the camera again I thought the lens had broken! Eventuakky one of my few remaining neurons woke up and I remembered that this had been mentioned somewhere - pulled the ring -all back to normal - pheww!
I must say that I am very impressed with the lens - very sharp and also easy to manually focus - just need to start taking good shots now (the difficult part)

[holidaydom]

Let me first say that I do not own this lens but have done some research on it...

To use MF on the SIGMA 105, you need to:

1) Switch the Lens from AF to MF mode so that the focusing motor is not powered.
With the Camera still in AF mode, it'll try to send signals to the lens motor but it'll not get through as the lens is switched to MF, thereby cutting off the focus signals coming from the camera.

2) Pull the Focus Ring backwards (towards the camera) in order to couple the focusing mechanism with the focus ring.

But if you try: AF on camera, AF on Lens, FocusRing on MF....
The camera will trigger and power the focusing motor in the lens to focus. But since you're holding on to the focus ring and it's coupled to the focusing mechanisms - the lens motor will have to work much harder to move the lens into focus as well as overcome whatever hold you have on the focus ring. This could potentially damage the lens motor and/or focus machanisms...

Again, I'm not 100% sure on the above as they're based on what research I've done while considering to buy this lens.

However, you can try to set Camera and Lens to AF and the focus ring to MF and see if the focus ring rotates when the lens is trying to focus.

Sidenote:
Notice that there are two focusing scales on the inner barrel of the lens. AF scales in white and MF scales in orange. MF will enable you to focus closer to the subject than with AF.

[henqe]

I do own this lens.

Originally Posted by holidaydom Let me first say that I do not own this lens but have done some research on it... To use MF on the SIGMA 105, you need to: 1) Switch the Lens from AF to MF mode so that the focusing motor is not powered. With the Camera still in AF mode, it'll try to send signals to the lens motor but it'll not get through as the lens is switched to MF, thereby cutting off the focus signals coming from the camera.

Well, the coupling is still on because the camera tries to reset the lens to infinity when powering down (if that's enabled in the menu).
No big deal though but stupid because the camera obviously knows the lens is in MF.

Quote: 2) Pull the Focus Ring backwards (towards the camera) in order to couple the focusing mechanism with the focus ring. But if you try: AF on camera, AF on Lens, FocusRing on MF.... The camera will trigger and power the focusing motor in the lens to focus. But since you're holding on to the focus ring and it's coupled to the focusing mechanisms - the lens motor will have to work much harder to move the lens into focus as well as overcome whatever hold you have on the focus ring. This could potentially damage the lens motor and/or focus machanisms...

Very true.

Quote: Again, I'm not 100% sure on the above as they're based on what research I've done while considering to buy this lens. However, you can try to set Camera and Lens to AF and the focus ring to MF and see if the focus ring rotates when the lens is trying to focus.

It does.

Quote: Sidenote: Notice that there are two focusing scales on the inner barrel of the lens. AF scales in white and MF scales in orange. MF will enable you to focus closer to the subject than with AF.

That is not true. The different focus scales are there because of the sliding focus ring as you just described. The lens has no trouble using AF down to 1:1

And to answer the OP: I never set the camera to MF (hassle), it's enough to switch the lens to MF. It's also best to slide the focus ring to MF although not 100% necessary.

I do find it stupid that Sigma included the MF/AF switch. The focus ring slide should be enough, now it takes two moves to switch to MF.

[gorman81]

Thanks for the informative replies - I tend to prefer the manual focussing myself - probably because I've been using a Yashica TL Electro film camera for about 20 years.

[holidaydom]

Thanks for the info and corrections Hedge

I have a couple of questions of my own actually...

1) With OLY lenses, I can set it up such that the camera performs AF and then I can fine-tune the focus manually right before fully depressing the shutter. (S-AF+MF mode on my E500) Is this possible with the SIGMA 105mm?

2) How is the focusing performance/speed of the 105mm as compared to OLY's macro, the ZD 50mm?

Thanks~!!

[henqe]

Originally Posted by holidaydom 1) With OLY lenses, I can set it up such that the camera performs AF and then I can fine-tune the focus manually right before fully depressing the shutter. (S-AF+MF mode on my E500) Is this possible with the SIGMA 105mm?

It's not possible in the Zuiko way. You can fiddle with the MF/AF switch after AF if you like.

Quote: 2) How is the focusing performance/speed of the 105mm as compared to OLY's macro, the ZD 50mm?

I have not used the 50mm but I hear it is slow. The Sigma is also slow, mostly because it can move the barrel sooo long. So hunting is extremely slow. For normal use (there is a focus limiter) there is no problem. When it starts to hunt I just let go of the shutter and halfpress again. Most times it starts over in the correct direction.

Quote: Thanks~!!

You're welcome!

As a sidenote, I love to walk around with this lens. I think it gives me a little different perspective on photography. I think 105mm and 2.8 make very nice photos, also portraits. And you can zoom with your feet

An example from the first day I owned the lens (my father):

[holidaydom]

Thanks for your input~!!

[henqe]

Can you tell I like this lens?

It's no Zuiko, not weather protected and no zoom. But gives nice results.

Perhaps a 50-200SWD with macro 1:1 would be something. Probably too many compromises though.

[holidaydom]

Originally Posted by henqe Perhaps a 50-200SWD with macro 1:1 would be something. Probably too many compromises though.

Yes - that WOULD be something!

As it is, there's currently no 1:1 macro from OLY except the 35mm
(although they claim that the 1:2 ZD50mm converts to 1:1 in 35mm terms...)