Sigma lens incompatibility with K7

Hello, this is my first post so please be gentle!

I've just upgraded from the K10D to a K7 and upgraded the firmware to 1.01. Early results look great but I'm still coming to terms with the new buttons/features/functionality etc

However, there is a compatibility issue with this camera and the Sigma 10-20 (not so with the K10) in that the AF SEL setting does not work - so I'm stuck with the 'auto' or 'centred' focus function.

I also have the Pentax DA 16 - 45, and the AF SEL setting works fine with this lens - which is probably how Pentax likes it.

Hope this helps.

It's understood that Sigma don't pay licence fees to the manufacturers, hence although their lenses work on existing bodies, by reverse engineering, when new ones come out they may well not do.

My conclusion is buy Pentax lenses for Pentax bodies, wherever possible.

However, the loss of one focusing method may not be too serious as most of us use centre spot focusing anyway.

Welcome aboard!

Thanks for that John.

I prefer to buy what I consider to the best lens for my needs as opposed to sticking rigidly to the body brand.

My 'needs' might be cost/quality/value/performance/reliability related or all of these factors.

Before I bought the Sigma - I had (still have) the Pentax DA 16 - 45 but since buying the Sigma, have never used it.

The two lenses were similarly priced (I think) but the Sigma is better, in my opinion, all round.

So, having upgraded, it's disappointing to discover that the lens is not fully compatible with the K7.

As you point out, it's not the end of the world, but it's just irritating that I've relaised (too late) that I cannot fully exploit all of the K7 features with my all-time favourite lens!

I wonder if you have a bad example of the 16-45.

G

Have I seen somewhere you can have Sigma lenses updated to allow them to work with a new camera model. Or was that specific to a certain lens/camera combination? Might be worth a call to Sigma.

They can be re-chipped by Sigma in many cases.

I have just tried my Sigma 10-20 on the K-7 and I do not appear to have any problems with AF sel. My K-7 has the V1.01 firmware and I have tried it with both settings of new config option "operate at AF point "sel"".

Do you get the little 4-way symbol at the bottom LH side of the view finder that indicates that the 4-way buttons are being used for AF selection?

My Sigma 10-20 is the older, non-HSM, version that I bought in March 2007. I believe that there have been some problems reported with Sigma HSM version lenses on the K-7. Is your 10-20 one of these?

Glyn

Thanks GlynM - I've been quiet on this for several hours because we've had an electrician round trying to source the cause of an intermittent electrical trip problem.

Since that's been resolved, I picked up the thread and had a look into the viewfinder to find the 4-way button icon referred to by Glyn above.

Now, ahem, this is going to be painfully embarrassing - but as I'm responsible for this thread, I'm going to come clean right here, right now.

I found the 4-way icon in the viewfinder (to my surprise) and clicked the 4 way controller fully expecting it not to work again, consistent with my experience since I uploaded the 1.01 firmware yesterday and again this morning.

You've probably guessed the rest.

It suddenly worked!

Don't ask me how or why - but it just worked and I kid you not I've tried this same process about 10 times over the last 24 hours, hence my post earlier today.

So, humble apologies for posting this incorrect information, sorry for wasting everyone's time and apologies to Pentax and Sigma too.

What else can I say?

There must have been a sodding mouse in there!

I'll get my coat!

Oh, and I have just sold all my Sigma lenses cheap to someone this afternoon on the basis they wont work on my new K-7 when it arrives

Don't worry it is so easy to get caught out with these complex devices. You are definitely not alone and this forum is here to help

On the K-7 the ok button is used to toggle between using the 4-way buttons to control the AF selection or for selecting the settings that used to be found under a separate function button on the K10 & K20.

Initially I found it a bit confusing and often could not workout why I could not move the AF point, and a couple times why some of the function settings seemed to have changed, all because I had forgotten to press the ok button. I soon learnt to check for the presence of the little 4 way icon in the view finder when I had enabled AF selection and if necessary press the ok button the make it appear.

Fortunately the new firmware lets you set the default function and I found it very useful to make it default to AF sel.

Glyn

Exactly what I have done Glyn

Glad to hear it, as anything else would have been mighty strange.

Was a bit confused when I read this as I'd just last weekend spent a long time with the 10-20 and K7 combo and not noticed any problems. Just checked again, AF SEL works fine on my camera/lens combo. I have v1.01 firmware and the f/4-f/5.6 variant of the lens.

Are you pressing the OK button before trying to move the AF point?
What have you got custom setting number 36 set to in the menu?

Duncan

Edit: Sorry, should have read the whole thread before posting..