What to buy to test chipped adapters on?

I'm new to EOS. JDM said "Friends don't let friends buy chipped adapters" and explained the risk that a fishy chip might fry the AF electronics. OTOH: I have a 5D IV, AFAIK there are no conventional user exchangeable manual focusing screens available for it + I've never been great at eyeballing SLR focus, so using it's multitude of AF spots behind adapted heritage lenses too feels very tempting to me.

My big question at the experienced community: Which old and inexpensive EOS body should I get, to test my adapters on, before I'll wager the 5D?

Is there something dirt cheap that uses the same batteries?

According to my current understanding 50 Euro should buy me a working 300D.

Whatever I might save on a film cheapo will most likely get eaten by a new battery?

An original 5D does tempt me in general but seems a bit too expensive for that purpose.

 

Thanks in advance for any input!

Each camera seems to require a different battery. That's my experience but I'm probably wrong.

300D, 400D, etc. OK, but remember, the older the camera, the older the battery it uses, and replacement Canon battery will not necessarily be much cheaper than for new camera. That said, try to buy something that already has two or more batteries with it. Its more likely that the batteries have shared the work.

My 400D batteries are getting a bit tired, but I can get by with charging them a bit more often.

The new Rebel type cameras like the 750D or 200D are pretty cheap compared to your 5D IV, and they might complement the 5D. Still it might be irritating if it blew up with a new adaptor.

Couldn't you borrow a friends EOS to test adaptors, and if it blows up, appear all wide eyed and innocent:eek::oops: I suppose not...

I'm thinking that the flaw/short circuit was in the adapter not the 20D. I tried a few on an EOS 650 ($25 or less) for test, but if the flaw was overpower to the sensor rather than the AF or shutter circuits, that wouldn't be a good test.

There are some good tutorials on manual focusing on line, btw.

I use the grid screen, not one of the MF screens on my various dSLRs in any case.

 

I took all of the chips off my adapters.

I don't know what a "chipped adapter" is but get the absolute best ...

I don't know what a "chipped adapter" is

An adapter to physically mount an off brand lens with an electronic chip glued on the metal that tells the EOS body that a lens is mounted and enables focusing assistance via the AF sensors.

"get the absolute best" is a bit tricky in this case.

Couldn't you borrow a friends EOS to test adaptors, and if it blows up, appear all wide eyed and innocent:eek::oops: I suppose not...

I was thinking about it but AFAIK I only have one friend with elderly EOSs. His film 5 seems a pretty decent camera*, the older digital is a 2nd generation and in his kids' regular use... When abusing friends' gear, I'd prefer a setting with adds checked and money for compensation or a replacement already on the table. I'd also appreciate having to blow dust of the camera in question instead borrowing one still in use. - I don't have that many friends... That's why I posted here. (*= I wasn't seriously into film AF SLRs but recall lusting after an EOS 50 kit those days.)

My batteries related worries were more about an aversion against buying non rechargeable ones for a film beater. I 'll be content with a "DC in" socket in a test platform never leaving the house.

There are some good tutorials on manual focusing on line, btw.

IDK what to expect from them. - I'm happily shooting rangefinders, I'll move linen testers over my view camera ground glasses, flip the magnifier into the TLR chimney but stay unable to tell if I'm nailing focus with a wide open 35/2.8 or 50/2 on a SLR. Stopping down did of course help, but what to do when I run out of ISO?

The key to dead on MF on a DSLR is (IMO) getting the proper focusing screen (in this case a split image or microprism one) and installing it. While I'm a huge fan of the 5D for this task (because of price & is FF), the availability of aftermarket focusing screens for them is minimal (although my understanding is that a Leica R8/9 focusing screen can be used w/ a tad bit of modification) because Canon, simply put, didn't make split image/microprism screens for the 5D (for whatever reason) . Just about every other model has them widely available though.

getting the proper focusing screen

Certainly, a specially-made-for-MF screen is good but I have found that it is possible to focus accurately even on the crummy APS-C built-in screens if you are very careful - rocking the focus back and forth to find the sweet spot, for example.

 

 

Many of these 'critical focus magnifiers' will fit on many eye-pieces, even today:

Why don't try Magic Lantern, it will give you all focusing options like zebra or focus peak, it is free, no need for "adapters":)

Magic Lantern

Must have been doing awesome things in the past, but don't support my Mk IV (yet?).