I was not aware that this was an STM lens... It's the EF-S 10-18mm. It could be, but I was caught out by the lack of a stop. I haven't had the lens long, and this was probably my first attempt at manual focus.

I know the focus point is not at the stop, especially in the more complex lens designs. It does give a starting point, though. My theory is to go to the stop, then start inching back, a tiny bit at a time. Without a stop, though, it isn't possible to tell where the lens *thinks* it is focused. The only target I had to play with was a white post at the other end of the parking lot. I could light that with my flashlight, and autofocus on it. It was no where near far enough away, though.

Part of the issue is the nature of a very wide-angle lens. For terrestrial purposes, you are either focused close or far. If you do not focus on something within 20 feet or so, then the whole image is pretty much in focus at 10mm. Ok, 16mm with the crop factor stuff. With the stars, you have to be much more critical, but I have not figured out a way of doing that which works for me.

My last SLR camera, back in the 80s, I had a 35mm lens. That was considered a wide angle. If you had a 28mm, that was a super-wide angle. I never heard of anything wider than that back then... I am sure that they were out there, but they were not something that most people ever came across. We are terribly spoilt these days, by the capability of the equipment that almost any of us can afford!

Ok, it has taken me a while to get to this, but here is the story of my perseid expedition...

Not wanting to be caught out with nothing at all, like last time, I took both cameras this time. My usual astro machine, the T4i (because it has the articulating screen) which was fitted with the EF-S 10-18mm lens, and my 7D, which had on the kit 18-55mm lens.

Both of them were focused in daylight, and wrapped with gaffer tape to keep them fixed.

I got up to my regular spot, and set up the T4i, took a test shot and zoomed in... It was *waaaaaay* off. I really didn't even need to zoom in to see that it was terribly out of focus. I had it on manual focus, and I tried shifting it just a little. This was when I discovered something odd. There is no infinity stop. The focus ring just goes round and round... I have never noticed that before, and it doesn't seem right. Is this something I should be contacting Canon about? For normal, non-astro stuff, it works fine on AF, but of course, at 10mm, pretty much is in focus regardless of what settings you use!

Anyway, I did have my back-up. I set that up and took a test shot, and it looked pretty good. Even zoomed in, it looked good and sharp. I spent an hour or so shooting in the same general area. I saw quite a few good meteors, but none of them were in the shot. There was a real good one which went right along the top of the tree line, but that was when I was trying to figure out the focus mess.

One reason I chose to shoot this particular field was that it contains my all-time favourite subject, M31. The books all go on about finding it by using the "great square of Pegasus"... I have never managed to identify *this* at all! Using Cassiopiea, it is *so* easy to find, though. Use the bigger of the 2 triangles as a pointer, and follow for about twice the 'height' of the triangle, and thar she blows!

You can imagine my disgust when I got home and uploaded everything, to find that the focus wasn't quite 'on' after all. They look ok, at 'normal' size. If you zoom in to 100%, however, everything is soft. Given the small size of M31 at 18mm, this is one which you really need to zoom in on, too. Bummer!

I am just about done with screwing around with this focus issue. I just can't mess around half the night (especially as I start back to proper work tomorrow...) and get nothing out of it. No matter what I do, it seems that I cannot get a good focus. Now, this is where I need some advice from the experts... Am I right in assuming that a *prime* lens will be focused on infinity if I just turn it to the stop? Is it the zoom factor which causes all the messing around, allowing the lens to focus *past* infinity?

I have a 28mm Vivitar f2.5 prime which I got from eBay. I haven't used it much because the field of view is so much narrower than the 10mm, or even the 18mm. For M31, I would *like* to try something bigger. All my long lenses are also zooms, however. If my assumption re the easier focus of a prime is correct, then I may go roaming the halls of eBay for a couple of other prime focal lengths, just to let me get *something* out of the heavens above!

There is always my trusty SX50, which does a marvelous job on the moon, but I suspect that focusing on M31 would cause me more heartaches with that setup...

*sigh*

EDIT: actually, the download looks half-way decent on here. It looks much worse in LR when taken to 1:1 view...

. . . In addition to the above, the new 50MP 5Ds has another feature, where you can crop the image in-camera to APS-H (1.3X) or APS-C sizes (1.6X), which also will reduce the size of the image file significantly. (However, it cannot be fitted with an EF-S lens that's designed for use on the APS-C Canon models.)

Nikon FX full frame models can accommodate their DX crop only lenses and will automatically switch to a cropped DX mode when one is fitted. This is not possible with Canon cameras. In fact, Canon's EF-S crop only lenses cannot be fitted to their full frame cameras at all. The bayonet mount is slightly modified to physically prevent EF-S lenses from even being fitted to the full frame cameras. . .

Enjoy

ATTORNEY: What was the first thing your husband said to you that morning?
WITNESS: He said, ‘Where am I, Cathy?’
ATTORNEY: And why did that upset you?
WITNESS: My name is Susan!
______________________________
ATTORNEY: What gear were you in at the moment of the impact?
WITNESS: Gucci sweats and Reeboks.
____________________________________________
ATTORNEY: Are you sexually active?
WITNESS: No, I just lie there.
____________________________________________
ATTORNEY: What is your date of birth?
WITNESS: July 18th.
ATTORNEY: What year?
WITNESS: Every year.
_____________________________________
ATTORNEY: How old is your son, the one living with you?
WITNESS: Thirty-eight or thirty-five, I can’t remember which.
ATTORNEY: How long has he lived with you?
WITNESS: Forty-five years.
_________________________________
ATTORNEY: This myasthenia gravis, does it affect your memory at all?
WITNESS: Yes.
ATTORNEY: And in what ways does it affect your memory?
WITNESS: I forget..
ATTORNEY: You forget? Can you give us an example of something you forgot?
___________________________________________
ATTORNEY: Now doctor, isn’t it true that when a person dies in his sleep, he doesn’t know about it until the next morning?
WITNESS: Did you actually pass the bar exam?
________________________________

ATTORNEY: The youngest son, the 20-year-old, how old is he?
WITNESS: He’s 20, much like your IQ.
___________________________________________
ATTORNEY: Were you present when your picture was taken?
WITNESS: Are you shitting me?
_________________________________________
ATTORNEY: So the date of conception (of the baby) was August 8th?
WITNESS: Yes.
ATTORNEY: And what were you doing at that time?
WITNESS: Getting laid
____________________________________________

ATTORNEY: She had three children, right?
WITNESS: Yes.
ATTORNEY: How many were boys?
WITNESS: None.
ATTORNEY: Were there any girls?
WITNESS: Your Honor, I think I need a different attorney.
Can I get a new attorney?
____________________________________________
ATTORNEY: How was your first marriage terminated?
WITNESS: By death..
ATTORNEY: And by whose death was it terminated?
WITNESS: Take a guess.
___________________________________________
ATTORNEY: Can you describe the individual?
WITNESS: He was about medium height and had a beard
ATTORNEY: Was this a male or a female?
WITNESS: Unless the Circus was in town I’m going with male.
_____________________________________
ATTORNEY: Is your appearance here this morning pursuant to a deposition notice
which I sent to your attorney?
WITNESS: No, this is how I dress when I go to work.
______________________________________
ATTORNEY: Doctor , how many of your autopsies have you performed on dead people?
WITNESS: All of them. The live ones put up too much of a fight.
_________________________________________
ATTORNEY: ALL your responses MUST be oral, OK? What school did you go to?
WITNESS: Oral…
_________________________________________
ATTORNEY: Do you recall the time that you examined the body?
WITNESS: The autopsy started around 8:30 PM
ATTORNEY: And Mr. Denton was dead at the time?
WITNESS: If not, he was by the time I finished.
____________________________________________
ATTORNEY: Are you qualified to give a urine sample?
WITNESS: Are you qualified to ask that question?

______________________________________
And finally:

ATTORNEY: Doctor, before you performed the autopsy, did you check for a pulse?
WITNESS: No.
ATTORNEY: Did you check for blood pressure?
WITNESS: No.
ATTORNEY: Did you check for breathing?
WITNESS: No..
ATTORNEY: So, then it is possible that the patient was alive when you began the autopsy?
WITNESS: No.
ATTORNEY: How can you be so sure, Doctor?
WITNESS: Because his brain was sitting on my desk in a jar.
ATTORNEY: I see, but could the patient have still been alive, nevertheless?
WITNESS: Yes, it is possible that he could have been alive and practicing law.

Had several failures both me and equipment, but the one I most remember was at a wedding I was photographing. Of course it was a big wedding and the parents were pillars of the community and important. In the first 3o minutes I was at the wedding doing the before the ceremony shots, I had two sync cords fail, a flash unit go out, a camera lock up, and a lens fail. Of course I had back up equipment for all and never missed a shot but glad all this happened at the start and not during the ceremony. I always had three of every thing when I went on location whether it was a wedding, portrait, or commercial job which saved me several times in the 30 active years as a professional photographer.