Is there any drawback of using more than one adapter?

[yalcinaydin]

I'm considering to buy some adaptall-2 sp glasses but there is not an original Tamron adapter for EOS mount, there are some Chineese made modelsbut I don't know how good they are. I've found an M42 Adaptall-2 adapter and thought that I can use it with M42-EOS adapter. Can using 2 adapters for just a lens have any drawbacks?
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My name is justthe first part of the nick: "Yalcin", and exactly "Yalçın"
- Canon 5D + EF 28-135 IS USM
- Olympus Zuiko 28/3.5, Olympus OM
- Asahi Pentax Super Takumar 50/1.4, M42
- Tamron Adaptall2 SP 70-210/3.5-4 (52A), Rollei QB
- Tamron Adaptall-2 28mm F/2.5 (02B), Rollei QB
- (Carl Zeiss) Rollei Planar 1.8/50, Rollei QB
- (Carl Zeiss) Rollei Sonnar 4/135, Rollei QB
- Rolleinar 2.8/135, Rollei QB
- Rollei Planar 50/1.8 HFT, Rollei QB
# WTB: Tamron 17/3.5, Tamron 80-200/2.8, Tamron 500/8, Pancolar 50/1.8, Leica-R 35/2.8

[Riku]

I have no experience with these adapters, but I don't think there will be any problems. Chinese adapters should be fine too.

[voytek]

My 3 cents
I think that the best way is go straight. Buy Tamron AD2 adapter mount for EOS. This way you have guarantee that everything will work together. What you are going to do if using one adapter on the second adapter finally wouldn't give you focusing to infinity? BTW - you wrote that you own [several AD2 lenses. Is it wort to make "savings"? Average AD2 adapter is always below $40, shipping included.
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BR, Voytek
Pentax K10d, Lenses PK, M42, P6, Hassel, PK medium, Mamiya, more to buy yet
flickr
photoSIG

[peterqd]

It's what I use, no problems. I keep the M42 mounts on the lenses to use with the 400D and the Spotmatics and change to PK mount for the Pentaxes.
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Lenses: M42 - CZJ 2.8/20, 2.4/35, 1.8/50, 2.8/50, 3.5/135 - Meyer/Pentacon 1.8/50, 2.8/50, 2.8/135, 4/200
Russian - J9, J21, J37A, M1v, M24m, I50-2, H44m-4 Vega12
Takumar 3.5/28, 3.5/35, 1.4/50, 1.8/55, 1.9/85, 3.5/135 - Vivitar 2.8/28
K-mount : Pentax-M 2.8/28, 1.7/50 - Tamron zooms :SP28-80, SP35-80, SP60-300, 80-210
DSLR:Canon 400D 35mm SLR: Pentax Spotmatic SP, SPII, SPF, ESII, K2, ME Super, P30 - Chinon CE-3 - Minolta XG-M - Praktica Nova 1B, PLC2
Rangefinder: Zorki-4, Beauty Light-o-matic III Medium Format: Yashica-Mat 124G

[yalcinaydin]

I've already purchased 5 M42-EOS adapters (they are all on the road:), I've bought spare ones for my 2 Minolta MD mount modification project) and one AF assist chip (intended to buy a complete adapter but got just the ship, my fault) so I had already made the expenses. I'll give a try for the Adaptall-2 M42 adapter as it's a lot cheaper than the EOS version.

For now I'll just buy a 80-200 f:3.8-4 cause they are really cheap and will look for fast (as I shoot mainly concerts) prime and zooms.

Edit, add:
I've bid 15$ for M42 adapter and was overbidden immediately so no need to increase the price as I can get a brand new chinese one for 20$. I will choose the EOS one.
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My name is justthe first part of the nick: "Yalcin", and exactly "Yalçın"
- Canon 5D + EF 28-135 IS USM
- Olympus Zuiko 28/3.5, Olympus OM
- Asahi Pentax Super Takumar 50/1.4, M42
- Tamron Adaptall2 SP 70-210/3.5-4 (52A), Rollei QB
- Tamron Adaptall-2 28mm F/2.5 (02B), Rollei QB
- (Carl Zeiss) Rollei Planar 1.8/50, Rollei QB
- (Carl Zeiss) Rollei Sonnar 4/135, Rollei QB
- Rolleinar 2.8/135, Rollei QB
- Rollei Planar 50/1.8 HFT, Rollei QB
# WTB: Tamron 17/3.5, Tamron 80-200/2.8, Tamron 500/8, Pancolar 50/1.8, Leica-R 35/2.8

[Flor27]

I'm using M42 Adaptall on an M42 -> EOS adatpter to use Tamron Adapall lenses on my EOS cameras. No problem so far with a goof M42 -> EOS adapter.

Please note than EOS Adaptall adapters sold actually were NOT made buy Tamron so they can be poorly adjusted as some M42 to EOS adapters...
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Switching from M42 to Minolta MD & Contax/Yashica