Jack Calypso

For those who can deal with a little bit of trig, here are three formulae for the relationship between Field of View A , Focal Length F , and Sensor Width W : A = 2 × (tan⁻¹(W ÷ (2 × F))) F = W ÷ ...

Another use for similar triangles: What focal length would cover that far-away subject? My thumb held up at arm's length is 27 inches away from my eyes, and it is about one inch wide. Estimate how ...

Good work! I did a number of calculations like this when figuring angles between shots for panoramas. At first, it looks (and is! :-) ) daunting, but then you start to see trends and patterns in ...

It's definitely a good idea to check out for special sales. Sometimes Canon's sales can make you go the other way. Several years ago, I got my EFs 17-55mm f/2.8 new from Canon for less than the ...

I buy refurbished whenever I can. I've never had any problems. You get a Canon warrantee and can add a Care package. The only real difference for me is that it comes in a generic  EOSPowershotVixia ...

You could avoid that by using manual  focus, but you'd still have to find the point. OP — I recall seeing some Web sites years ago where people would post theirs, but it wasn't clear to me how to ...

I always check the "Show only sold listings", to see what people actually paid for the items.

I'm curious what Canon's sales of the R7 are, compared with the R6.

One thing not to use is a mild solution of dish washing liquid. My optometrist told me many of them contain de-greasers, which can damage lens coatings.

SmallRig used to have a plate for attaching to the bottom of various cages, but it is discontinued. https://www.smallrig.com/smallrig-arca-type-quick-release-plate-for-smallrig-cage-apu2389.html It ...

The tactile element is what I like (the audible helps too). I can work faster if I don't have to look at the camera after the initial setup, to better deal with moving clouds and changing light.

I was referring to the flat, slotted, adjustment next to the mounting hole.

I hadn't seen that; it's not on the Leofoto USA site. What does the adjustment screw on the top do? I do like the Nodal Ninja one for the large knob.

Another thing to consider is how the upper rotator works. I shoot a lot of multi-row panoramas, and I like one that has detents, since it allows me to work faster, to deal with changing light. The ...

Yeah, buildings are often pretty far away, and atmospheric heat shimmer is the bane of my existence.

I received the 2X from Canon, just in time for a bunch of gray, windy weather conditions, so I haven't been able to check it out properly. The Sun did break through briefly, so I set it up on my ...

Zooming would, but I don't see why one would do that. It was easier to find back in SLR days. Now, I just say, "Eh, it's near the front of the lens", and make sure there's no subject too near the ...

I've been following this thread, as the 200-800 would slot in nicely to my current kit. I have a few shots in mind that would use the reach, but have to be done soon for the Sun to be right, so ...

And, of course, with an EF mount, you could use them  with an EF to R mount adapter, should you go that route.

Since both EF and EF-M are discontinued, you won't see any new lenses in these mounts, so if you find one you want, I would buy it now.