Frank is talking of medium format, where the bigger sensor gets less DOF.
Apertures work the same way, but a smaller aperture will be needed to get the same DOF. If you've got used to f16 giving enough DOF with APSC it might not be enough for 645...

Welcome to PU Frank, I hope the switch to 645 works out well for you!

Aperture is indeed a ratio, it's the ratio of the opening through which light can enter to the focal length of the lens. It's often abbreviated.

There are a few that are missing from my collection. If you have those I'd certainly be interetsed - I'll check which I'm missing & get back to you
Mike

We used to have a cat that would often join us on Dog walks. (She would usually go back after half a mile or so)

Nothing like this though!

I've often followed blind links such as this to find they go to a video clip that exceeds my allotted bandwidth. Generally now I don't bother with them. So I quite agree some description of the link would be a benefit.

Should make for more interesting photos than a full moon IMO.
The moon tends to look better when not quite full.

The heavy winds & rain definitely weren't ideal for our club photo display today (part of the Clacton Carnival 'Fun day').
The Marquee we were original due to be sharing with a local artist, apparently disappeared in the night, so we had to make do with an open fronted Gazebo! Fortunately some of the mounted prints could be swapped for Laminated ones So I think things worked out as well as could be expected.

Spot metering generally gives reasonable results, but I wouldn't make it any longer it very easy o blow out all the detail in the moon. Its (nearly always) in full sunshine so quite bright, while all around it is effectively black in most shots.
Despite the common view that the moon is up at night, it's actually in the day time sky just as much as the night time sky. However most of us only photograph it at night where its so much more visible.

IIRC the guide for the moon (nicknamed looney 11) is similar to the sunny 16 rule but with f11 instead of f16.
ie use 1/iso seconds at F11 & adjust as required for f stop.

Your unlikely to have a lens that can't fit all the moon in, even a 1000mm lens leave plenty of sky.

The moon moves surprisingly fast at these sorts of magnifications so you'll need to shot fairly fast. (DOF is not an issue)

The line before that too, though I might extend it to a week before & after.

Spring tides are due to the addition of both solar tides & lunar tides i.e. The gravitation bulge caused by the sun adding to that caused by the moon. You'll find they always occur at full moons & new moons, when the sun is in line with the moon, which strongly suggests the distance of the moon is not the controlling factor for this phenomena!

There is however a 'Proxigean spring tide' which is a particularly high spring tide when the moon is at perigee. These occur roughly every 1½ years, though of course some are significantly bigger than others. Apparently the extreme ones are about every 30 years.