I wouldn't worry about the specific distances. You are over thinking it, for now. Let the auto-focus do it.
If in manual focus, you could use it as a starting point. Personally I seldom bother with those numbers. When manual focusing, look through the viewfinder and turn the focus ring till the image is sharp. Click!

The focal plane on a Nikon is market by a zero with a horizontal line through it. It is painted white and marked on the top of the camera behind(closer to you) the right camera strap anchor bracket, usually. That is where the sensor is inside the camera. The distance is from that point to the subject, unless you exceed the lens' maximum. Then you will be at infinity(the sideways 8). Get it?

Call me crazy, but I couldn't pass up the deal on CatMarley's pristine Mamiya 645 film camera. Herein lies the issue. I haven't shot film in years (15+), let alone 120 film (not since I was a 10 year old, 29 years ago).

I do have the luxury of a pro camera shop across the street from me, where they still sell and process 120, so I'm sure they will be a great resource for me. However, I'd like to do some reading up on understanding this format so I'm not so clueless.

Where do I start?
I've already downloaded the manual (or should I say, a scan of the manual).

I'm very curious.........how many people on UHH actually use the metric system? I realize everyone in the U.K. and Europe does, but I'm wondering about the extent that people in the U.S. ever use it, or how well most people here understand it.

I have a couple reasons for asking; one of them is, just today one of my "libertardian adversaries" made a remark about the fact that I had posted 365 "right-wing" "reactionary" articles, yada, yada, blah, blah, blah since.......

About a week ago, something caused me to start thinking again about the metric system, so I thought, "if I post something that I've written myself, it will possibly "calm him down" a bit! (or maybe even give him a month long headache! )

Anyway......getting back to the metric system.......I have a good friend who runs a sign business in his spare time; for the last 2 or 3 years, he had a big 4 ft X 8ft CNC routing machine which was made in the U.S. Although a machine like the one he had runs around 15k new, it's still a very basic machine, as CNC machines go, and it was designed and built primarily for hobbyists, etc.

Several months ago, my friend told me he was selling the machine he had, and ordering a new one that's made in China; it took 3 or 4 weeks for the Chinese company to make the thing, then when they shipped it, the ship took almost two weeks to get to L.A. then it took Customs a week to clear it......and finally it was on a train, headed for Indianapolis! (This was back when we had all the big snow storms ) because he was tracking the thing every day, he could see exactly where it was each day, and then the train was "delayed" a time or two by the heavy snows. Finally.....the train arrived in Indianapolis......but now the Customs in Indy have to "check it out again"! When they finish checking it, a "fly by night" air freight company has to pick the thing up at the rail road, move it across town to their terminal, and my friend is to pick it up there the next day; he gets another friend of mine who has a 16 ft trailer to go to Indy to pick it up; they arrive at the freight dock, measure the crate the machine is in, and determine that although the crate will fit on the trailer bed, it WON'T fit between the trailer wheel wells!

(It's about 65 or 70 miles from here to Indy; they drive back home with the empty trailer, and my friend rented a bigger trailer from an excavator we know; this time he drives back to Indy the next day, which is Saturday; now there are only a few people at the freight company; because they don't have a BIG fork lift, two guys get on two "dinky" fork lifts, and one of the guys is a total "klutz", and proceeds to bang into the big crate, tears the crate to smithereens, all while my friend Robert is watching! Then he tries to say it was "already torn up"! For once in his life,
Robert is now "speechless"! He has already paid the company in China almost 25K, (plus $3,500 to ship the thing from China to the U.S. and he's not about to sign for something that the crated is torn up! Back home again with the $100 rented trailer! (I offered to let him use my trailer, but my plate expired in Dec.) at this point, it looked like the machine was going to be going back to China!

Come Monday, Robert called the insurance company; (he had wisely insured the thing when it arrived in L.A. ) The insurance company saved the day! They told him they would sign for it, and for him to take it home, have his friend drive down from Toronto, Canada to wire the thing up, and get it running so they can determine if it's O.K.

Next.......Jamie arrives from Canada, (this guy's a genius, and has a machine very similar to this one, plus, being from Canada, he "into the metric system", right? )
As it turns out, Jamie buys his gas "metric", reads the thermometer in metric, but when he's using his CNC machine.........he measure everything in "feet & inches"! (I still can't believe it! )

They get the machine wired up in 10 minutes; but the computer in the machine "understands the metric system"
so Jamie says, it's not a problem, we'll just have to "teach" the thing "feet & inches"! (Being a genius, Jamie had the thing going after an "all day" "figuring out" session, and next day he and his wife head back to Canada; ) the next day, I'm back down at Robert's, and he's about to start cutting a big piece of sign foam; (which costs $200 ) when he had the program loaded in the machine, he starts it up, the spindle travels all of 6 inches, and BANGS into the sign foam, breaking the carbide router bit! Robert was......"puzzled".......then he says, well, at least it broke the "cheap one"; he picked up another bit the same size, says "this one cost $65, but the one that broke was "only" $18! (I'm thinking..."what luck"! )

So far, that's the "bad news"; but there's also "good news"!
Before the machine left China, Robert decided he would become the "U.S. Distributor for the Company in China; (he had already ran ads on the internet; before HIS machine had left China, he had already sold a bigger machine to a company in LA! (Two more sales and this machine has paid for it's self; )

Apparently it's not a "big deal" to convert these things to understand feet & inches; And I asked Robert......why not just "convert YOU" to use the metric system! It's so EASY! It's so much more sensible! (I've been using the metric system to facet gem stones for the last 20 years! ) I even used it to build a big antique case clock; why is everyone so adamant about using mm's an cm's to measure things?

Now that I've shared that little story, here's something I learned a while back that really astounded me; I read constantly; I was already somewhat familiar with metric from faceting and working on cars and my Kubota; I already "knew about" cm's , mm's, microns, nanometers and even angstroms; but that's where my knowledge of "small things metric" stopped.......with angstroms; for a long time I just assumed that angstroms were the smallest unit in the metric system; then about 5 or 6 years ago when my wife and I were selling antiques, I spent a lot of time rummaging around in junk shops, auctions, etc and I was selling a LOT of used books; one day I ran across a whole big box of old Nat Geo magazines; (maybe a hundred of them in the box ); I forget now exactly what I gave for them, but it was no more than maybe a a nickel or a dime a book; I knew I could get at least 50 or 75 cents apiece for them, so I brought them home; needless to say, I cant resist Nat Geo's, so I had to read them all before I took them to the antique shop; going through this one I ran across a story about electron microscopes; (I have wanted to read about electron microscopes for half of my life! ) (I even started to buy one once on eBay! (until i found out the thing took up a whole room! ) Probably the most interesting story ever published in Nat Geo! I've probably read it 25 times by now! And that's when I discovered the "************* which is 100,000 times smaller than the angstrom!

My question is......what's it called? (don't cheat and go run to "wiki";) (if it's even mentioned there. )

Because all of this information was so.......so..."profound", I spent 2 or 3 days making a very nice (if I may say so myself ) "chart"; in a couple of days, if I can get any "guesses", I'll put the chart I made on here; (this "thing" I'm referring to is like ten trillion times smaller than the centimeter; and I think, 100,000 times smaller than the angstrom.

Hi guys and gals,

Has anyone any experience of sciatica?

Out of the blue one evening I felt a sharp little pain in my buttock/hip area. By bedtime the pain had spread to my upper thigh and whole hip/buttock area. the pain was really intense so I took paracetamol but could sleep all night for it. The pain level set me thinking back to the last time I experienced that level of pain and there ware two incidences. First one was during childbirth 43 years ago and the second time was after having a hysterectomy. They discovered I had an internal bleed and had to go to theatre again the next morning so they withdrew my morphine all that night. It wasn't at all pleasant, I can tell you.

So if anyone out there can explain to me what sciatica should feel like it would help as I feel the doctor is fobbing me off. Even when I am in excruciating pain, I have no loss of flexibility or movement and when I do move it has no effect on the pain, making it neither better nor worse. The doc has told me that my symptoms are not of classic sciatica but was unwilling to have any tests done to prove it or otherwise but my daughter came with me and forced the issue and managed to get him to agree to have an xray and blood tests done and I'm now waiting for a scan.

I'm not one for running to the doctor unless it's necessary so if anyone knows of something in the way of self-help that they have used and proved beneficial...I'd love to know.

Basically, I'm on 2Ibuprofen + 2 Paracets + 2 Tramadol, just to keep the pain at a manageable level..... and I'm definitely not a pill popper. I rarely ever have to take painkillers as I don't like the fuzzy head they give me.

So if anyone out there has ANY helpful self-help knowledge I'd be eternally grateful.

My new SonyRX100 has arrived as well as the Guide by R White but my heads been too fuddled to feel like tackling it. I'll update you all as soon as I've trialed it for a bit.