TTL problem with HSM lenses.

I have just bought a Tumax flash, which does not seem to work in TTL mode with my two Sigma HSM lenses, but works fine with older, manual focus lenses. With the two HSM lenses, aperture, ISO and f stop don't show on the flash, so it only works in manual. Does anyone know why this is? I assumed the information is sent by the camera, not the lens, but this does not appear to be the case. Does anyone know how to fix this problem, or am I doing something wrong?

Which model?

Best regards

Are you sure that the older lenses are not using full aperture?

G

It's a DPT386AFZ. Bizarrely, a few minutes ago I discovered that it does in fact work with these lenses, but you have to switch the flash on before switching the camera on, which I don't have to do with other lenses. In fact, it seems to work very well, even at 10mm using the built-in adapter thingy, so I am now very happy with it, especially considering what I paid for it.

So it's back to defcon 4.

Best regards

Interesting flash! There doesn't seem to be much info online, would love to hear a mini review after you've given it a test drive

Manual (what there is): www.icorpandtumax.com/uploadfiles/file_49101577a037c.pdf

There seem to be other models available on eBay as well...

Matt

I bought the flash in Hong Kong and strangely the shopkeeper persuaded me to buy it instead of a Metz 48 he had for a lot more money. He said he has been selling them for a while. Maybe he was hoping I would splash out on the amazing collection of Ltd. lenses he had in stock! I will give it a proper try out soon but very busy with work at the moment. Also got a price list for ltd lenses I need to compare to ebay but I think I will be going there again. It was the only shop I found with a good collection of Pentax stuff although a lot of shops had the Kx in stock.

Which shop was that? I'll probably be in Hong Kong around Easter time.

Tim, the shop is Wing Shing Photo Supplies, and is on Sai Seung Choi St. in Mong Kok. They actually have three shops, but this one had the most Pentax stuff. They have a website too link but it's mostly in Cantonese. I've been comparing the price of Ltd. lenses and they are a lot cheaper there, so next time I am back I will drop in. The guy running the shop is very helpful.

Thanks AG, I know the street, will have a look next time I'm back there! If I'm on your plane I'll be asking if you have any spare seats up front!