Question for users of more than one Sigma lens

As per another thread, I am considering buying the Sigma 70-200mm 1:2.8 DG OS HSM lens for low light motor sport use because my longest f2.8 lens is the DA* 50-135mm. I also have a Sigma 180mm macro lens as well, hence the question.

If you own more than one Sigma lens and you've made AF adjustments in-camera to fine tune the lens/body auto focus, does your camera apply individual AF adjustments to each lens or does it apply the same adjustment to all of your Sigma lenses.

This might happen because Sigma lenses are not identified by name like the Pentax lenses are, and possibly others.

I've also asked the same question in my other thread so if you've answered there, thanks. I've asked the question again here because some users of multiple Sigma lenses may not visit that topic.

Peter,
Not that I can answer your question directly, but it _may_ be that the Sigma lenses still identify themselves through the two-byte lens ID tag. PhotoME should show that value (even if the name isn't shown).

So, if you use PhotoME to get your ID value and get someone with the 70-200 to do that too you should be able to get your answer

EDIT: I think it's Lens[ID] and is shown as 4 bytes (not two), e.g. 2+241+0+0 = DA*50-135, 2+242+0+0 = DA*16-50

EDIT: Crogram FilesPhotoMEdatamakernotespentax.xml contains an interesting list of lens names and includes a few Sigmas.

Assuming the tag values are different, I would imagine that the AF adjust should cope.

Matt

Hi Peter
The camera recognizes each different lens. How I don't know but it is an impressive feature of the Pentax cameras!!
cheers
bb2

@Matt, I did wonder if the camera would use the lens ID tag.

@BB2, thanks for the feedback.

Not actually correct.

My old Sigma 70-200mm and 100-300mm f4 used the same ID code (which is how the camera identifies and knows how much adjustment to use for each lens)so each time I used either lens I had to change the adjustment manually.

Not having a 100-300 F4, I never had that problem.
cheers
bb2

I've checked an image from my 180mm lens with PhotoMe and it shows the Lens ID as 3+0+0 and correctly identifies it by name as a Sigma 180mm EX DG Macro lens.

An image from a 70-200mm sent to me by Mike has the lens ID as 8+23+0+0 but the lens is "Unknown". PhotoMe hasn't been updated for some time now so I'm guessing its lens database is out of date.

Hopefully this means that the two lenses (if I buy the 70-200mm) will have separate AF adjustments stored by the camera.

Peter.

Lens adjustment ?.

I have three Sigma lens, plus four Pentax lens, used on a K10 and K5,I have never made any lens adjustment on either camera as both cameras accept all the lens without any problem.

Take care.

You are maybe very lucky then Chris. I, like many here, have had to make AF adjustments for most of my lenses.

If Chris is lucky, then so am I, so is Sue, so are brother/sister-in-law, in fact lots of photographers we know as well, including many professionals.

Still, we digress, and no doubt we all act as we find things.

Nope ive never adjusted AF either. But I thought about it...

I feel a poll coming on

I have a Sigma 17-70 & 100-300 and my camera can tell the difference.

I hadn't really given it any thought about how it did it.

Somebody reply to JRs post before I get myself banned!!!!!!!!!!!

Whatever it is you are all on... can I have some?

Many, many professionals do need focus adjustment. That's why Pentax put the custom option in their higher end dSLRs

Of course, it's probably not noticed at f/5.6 and smaller. At f/1.4 it's really important!


On a side note... my K5 had to go back for a replacement mirror motor and JPSS kindly calibrated the K5 + DA*16-50. Interestingly, the other lenses are more accurately focused too - but none of them 'perfectly'

Matt