Charles Hamilton

OP here; let me clarify what I was actually trying to determine. I shoot an APS-C Canon DSLR and have a Canon EF zoom that tops out at 300mm. I had the opportunity to buy a righteously-priced Canon EF-S zoom topping out at 250mm. I wanted to know if the focal length of this lens would effectively be 250mm x a 1.6 crop factor giving me essentially a 400mm lens. I posted the fixed 200mm lens example in the OP because it was a cleaner, simpler question to respond to. It would yield the same info I wanted— but with less chance of off-topic zoom lens range/image quality/speed/flare, etc. issues muddying the thread. Thanks to all the good info I got here, I learned that the 250 lens would in fact NOT get me any closer to the subject I was shooting. So I thanked the guy selling the EF-S lens, told him I wan’t interested and hung onto a few bucks I didn’t need to spend. So hey guys, the next round is on me…

Thanks all-- I've got it now!

So...if I'm understanding.. There would be no difference in how "close" the lighthouse appears in either photo and the same distance of terrain on either side of it-- say 100 yards out each way, though there might be differences in image quality. In other words, in a quick, superficial look at the two photos, the subjects would appear pretty much the same-- image quality not withstanding.

Say I have two Canon 200mm lenses-- one EF and one EF-S-- and mount them on two identical model Canon APS-C cameras to shoot a distant light house. Because of the crop factor, the subject shot with the EF-S lens will appear closer up. Yes? No?

If I was designing that product, I sure wouldn't rely on the dimensions some guy on a camera forum quoted!

Thanks, it's Dynachrome...

Yup, that's it! Thanks... I've still got many boxes and carousels loaded with those slides. They're 50+ years old and except for a handful with some fungal growth, still project bright, saturated and crisp images belying the gloom and doom predictions of those brutal 60's Kodachrome Fan Boys!

Those don't ring a bell...

For the life of me, I can't remember the brand name of the 35mm slide film I used to shoot in the late 60's and early 70's. It was a good bit less expensive than the Kodak films and it came with a mailer that included processing. I think it may have been manufactured by 3M...

Marcus and Mark, thanks for those great solutions!

Thanks for the tip; pretty inexpensive way to go. I think I'd have a hard time, though, going back to manual flash. I don't have too many pleasant memories of the distance-estimating and mental math using a Spiratone flash on my Minolta HiMatic 7s and SRT-101...

Oh well. Thanks for the detailed response though!

Can the popup flash on an EOS Rebel T6 be the master and wirelessly trigger a slaved Speedlite 430EX II-- or is a transmitter needed?

<p>I mistakenly purchased some class 10 *Micro* SDHC flash cards instead of full-sized SDHC. Is it OK to use the micro cards with adapters in my new EOS T5 or should I get full-sized ones?</p>