help repairing lense

[Joshua Bunn (Joshua)]

Hi All,

I recently got a bargin deal on some camera and lense equipment, in the package came a RMC Tokina Macro Focusing Zoom 100-300mm lense, see picture. The lense has some movement in the direction perpendicular to the optical axis (there is no slop when zooming or focusing). Does anyone have experience or know how this lense is taken appart so i could try to repair it?

I see there are some screews, and this is where i will start i guess if i dont get any responses.

thanks
Josh

[barx1963 (Malcolm)]

You're a braver man than I Gunga Din!

[gregbradley]

I'd take photos of every step you take so you know how it goes back together later on.

Greg.

[Joshua Bunn (Joshua)]

Thanks for the replies, Thats sound advice Greg. BTW Greg, Have you got a SMC Pentax 67 45mm lense or used one? What do you think of it if you have?

Josh

[KG8]

Madness! But if you really want to go ahead I would get a junker zoom from somewhere and practice on it first. Even an expert repair technician in the field I went to years ago refused to pull apart a pentax zoom to remove growth on the lenses inside. He sprayed it with some stuff that killed the growth and sent it grey. I tried once myself once with a cheapy and ended up with a pile of greasy glass. Grease everywhere in a zoom, take care.

[GeoffW1 (Geoff)]

Hi,

I've never ever done this, so this reply doesn't form part of the substantive response I hope you will get. The subject fascinates me though, I notice a lot of traffic on this in photo.net, eg

http://photo.net/canon-eos-digital-camera-forum/00AGOo

I don't mean to be a distraction, so I am tip-toeing here, but I'd love to know

Cheers

[koputai (Jason)]

I've fixed a few myself, it's not a biggie, just be sure you know the exact order everything came apart, and which way around it goes. Keep each set of screws in ordered containers.

You'll need some very small screwdrivers, likely both Philips and Blade. You may also need a 1.5mm Allen key.

Just take it gently and you should be ok.

Cheers,
Jason.

[Joshua Bunn (Joshua)]

Thankyou everyone for your replies. There are some mixed responses and i value them all. Not really sure what im going to do with it to be honest, I havent examined the image it produces yet, so I should probably do that. Also i thought of putting an eyepiece holder on the back at the right distance and using it as a variable FL finder scope for my scope,.

To use them on my canon Eos, i need an adapter with an optical element in them to achieve infinity focus, if im not mistaken, which would compromise image quality. Not realy something i want to do.

Probably better to get a dedicates EF lense.

thanks all

Josh

[koputai (Jason)]

Originally Posted by Joshua Bunn

To use them on my canon Eos, i need an adapter with an optical element in them to achieve infinity focus

Joshua, that depends on which camera the lens currently has a fitting for.

Here is a page that lists flange focal distances for various lens systems. You'll see the Canon EF system has an FFD of 44.00mm and if the lens is currently fitted to a system with an FFD longer than that, your adapter won't need an optical element.

For example if your lens is made for a Pentax K mount, which has an FFD of 45.46mm, then you have 1.46mm to play with.

Being a Tokina lens it probably already has an adapter on it to suit whatever it already mates to. You may be able to take this off and then you'll have more space for a non-optical adapter to EF.

Cheers,
Jason.

[Joshua Bunn (Joshua)]

Thanks Jason,
The lense currently has a FD mount, there doesnt seem to be any aditional adapter on the lense other than the native one. You forgot the link , but would the FFD be the same as the canon FD mounts made for the older canon cameras, ie 42mm, as it connects to that camera?

thanks
Josh