November 28, 2014, 06:29:48 AM

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Messages - Valvebounce

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1
Hi dgatwood.

dgatwood link
Either you have way more patience than I do or you're unfamiliar with the concept of testing and binning.  Most modern electronics go through an extensive, fully automated testing and binning process.
This:-[ :-X
Similarly, when it comes to cameras, the tolerance isn't the main problem.  The fact that the user has to calibrate it straight from the factory is the problem.  In a sane world, Canon would connect the camera to a test rig using a fixed-focus lens and a target at a fixed distance.  The camera would then compute its own base AFMA for each individual focus point in the camera, and would store that data permanently in an EPROM or flash part.

Similarly, for a lens, in an ideal world, Canon would attach it to a test rig consisting of a permanently mounted camera and target, and that modified camera would compute AFMA values for the lens at various zoom settings, and would then program the lens with a series of focus offsets, so that the lens would always focus correctly with zero AFMA (assuming the body was calibrated properly).

When you're talking about a lens that costs thousands of dollars, there is simply no excuse for having to manually calibrate the lens to compensate for significant copy variation.  When a lens or camera arrives from the factory, it should have an AFMA adjustment of zero.  It should "just work", and no lens/body combination should ever require more than about ±1 AFMA.  Anything less than that level of consistency is just plain sloppy, IMO, and reflects a lack of adequate burn-in testing and factory calibration.

I don't know what the scope is for automating this process, would it require quite a high human interaction to mount and dismount each item, thinking lens release button?
I would imagine that each machine would be costly, plus use a lot of floor space, thinking test an 800mm lens, plus there would be a requirement for more than one of each, routine calibration etc, I still see the price climbing, though possibly by a much smaller margin.
Again I find I am educated by the diverse range of knowledge here. Learning a little every day helps us know we are still alive!

Cheers, Graham.


2
Animal Kingdom / Re: BIRD IN FLIGHT ONLY -- share your BIF photos here
« on: November 27, 2014, 06:38:11 PM »
Hi GraFax.
Yep that's kind of what I was getting at when I posed the wing fence question! But then they have been at it a bit longer than us!

Cheers, Graham. 

You guys are taking me back to my school days. Laminar flow and boundary layer separation. I don't remember much but they do seem to use the winglets to regulate their stall speed. We still have a lot to learn about flying from birds.

3
EOS Bodies - For Stills / Re: 7DMKII Focus keeper rate ideas?
« on: November 27, 2014, 03:33:17 PM »
Hi Domino Dude.
I was aware of that, what I was referring to was how many 0.001mm manufacturing errors cause 1 AFMA unit of correction to be needed.

Cheers, Graham.


To answer the question about how much is 1 unit on the AFMA scale: It is 1/8th of the current lens DoF at its widest aperture.

Edit: Adding source to the above. Rudy W @ Canon, as described in this article -> http://www.learn.usa.canon.com/resources/articles/2011/af_microadjustment_article.shtml

4
EOS Bodies - For Stills / Re: 7DMKII Focus keeper rate ideas?
« on: November 27, 2014, 03:18:29 PM »
Hi Sella.
I give a plus one on that! But then I don't think I need help from someone with ologist in their title, I could be wrong?

Cheers, Graham.

That said, if your psychologist had that reaction from this thread, then she's obviously not ready for the real world.

5
EOS Bodies - For Stills / Re: 7DMKII Focus keeper rate ideas?
« on: November 27, 2014, 09:44:43 AM »
Hi Sella.
I read posts like this and realise you either have bottomless pockets stuffed with money or lack a clear understanding of manufacturing tolerances.
To have to calibrate a lens to a body is in my opinion not only acceptable but necessary. Each body and each lens are made to a plus or minus tolerance, measured in 0.01 or 0.001mm or even smaller! If both lens and body are middle limit, or out in complementary directions, ie the tolerances cancel all will be fine, if they are out in the other direction the tolerances are additive, I suspect each lens and each body is allowed + or - 10 AFMA POINTS and given this, a worst case scenario could see you needing all 20 AFMA points. (I don't know how many bits of a mm = 1 AFMA point)
To halve the tolerance range could add a significant percentage (I don't know how much so I won't quantify it) to the cost through extra manufacturing time and component scrapage! And then what you still have a tolerance, yes smaller, and still need to calibrate! So halve the tolerance again, can you see where this is going? Except the next reduction will cost more than the first reduction!
Personally I'd sooner be able to afford a camera and lenses and calibrate than dream about equipment that is perfect, + or - 0.0000000mm and doesn't need calibration.
14 yrs toolmaking working to tenths of a thousandth of an inch so I know a bit about increase of time with lower limits and scrapage rates. Conversely I don't know how much they would cost Canon as I don't work there!

Cheers, Graham.

With current technology, for the 7DII to exhibit any form of AF problems is in my opinion totally unacceptable. This is a professional-grade camera and to expect any professional (where time equals money) to first calibrate the lens and camera combination is just plain wrong. What will happen if such a professional photographer rents (or borrows) a lens at the last moment, but must now spend an hour first to calibrate the combination? That is if he actually has his calibration tools with him!

Any professional-grade equipment must work 100% perfectly straight out of the box.

6
Animal Kingdom / Re: Show your Bird Portraits
« on: November 27, 2014, 04:29:13 AM »
Hi Ken.
Very nice timing, looks like a bit of a mouthful!

Cheers, Graham.

Lunch time!

7
Animal Kingdom / Re: Show your Bird Portraits
« on: November 27, 2014, 04:27:02 AM »
Hi Jack.
Very nice shots, I think the flash is serving to enable a shot that would otherwise be for you, at an unacceptable ISO, therefore it really doesn't matter that much about the slightly flat flash lighting.
I'm sure someone will correct me if I'm wrong, but I think if you are within the reach distance of the flash, it matters very little about the focal length of the lens, perhaps the flash light is a little more spread with respect to the area covered by the lens, but I think the ETTL will take pretty good care of that.
Do the birds come to basically the same spot? Could you move the flash closer, cheap lead or not so cheap RT remote trigger?

Cheers, Graham.


Those of you who are long time regulars may remember me showing up on CR not quite 2 years ago after purchasing my 6D.  I had shot one year with a Nikon D5100 and was really getting the bug.  I felt insanely uneasy having just spent $7k on the 300 2.8 II.

Uneasiness is long gone and I don't have any regrets on my purchases for sure and am enjoying learning.
Yesterday, I decided to buy a 600 EX- RT but I haven't used flash for 20 years.  I liked the idea of fill flash for wildlife and some of you have previously advised me in that direction.  So, now I need to come up to speed and am reading and experimenting.

Being late November here in Alberta it gets pretty dark around 4 PM and to boot it's been cloudy.  The result is that often I get shots from my observatory on the barn with natural light, at ISO 12800, which I don't really like.  It's just occurring to me that to have fill flash you have to have good natural light in the first place.

Anyway, that's the background and here are shots at sundown, 6D 70-200 F2.8 II X1.4 (HSS) that I'd appreciate feedback on.  Would these be considered acceptable or is the flash creating too much artificiality and if so any suggestions to correct that.  I might be able to rig up some kind of reflector for bounce but being outdoors it's not that easy, not to mention winter winds and snow.  Plain honest commentary is fine! :)

Jack

8
Animal Kingdom / Re: BIRD IN FLIGHT ONLY -- share your BIF photos here
« on: November 27, 2014, 04:12:25 AM »
Hi GraFax.
Very nice shot, well done.
I wonder how the aircraft engineer/designer first came up with the idea of wing fences!  ::)

Cheers, Graham.

Here's a nice look at the wing profile in flight. For those interested in fluid dynamics and such....

9
Canon General / Re: Your favorite photography magazines & books
« on: November 26, 2014, 08:54:53 PM »
Hi Mitch.
You possibly missed the point, I have some 30 plus issues downloaded in ibooks, more than enough for any flight, throne time, tea break, or the inlaws, and all in less space than one paper edition! ;D
If you mean paper based then I sporadically buy any photography magazine that has an article that I find interesting, about twice a year. Other than that I get car club mags from 3 car clubs on a bimonthly basis each, more than enough reading to keep me busy.

Cheers, Graham.

10
Canon General / Re: Your favorite photography magazines & books
« on: November 26, 2014, 08:09:30 PM »
Hi Mitch.
I get most of my info and education here! When I don't have an internet connection, (like some lunchtimes at my workshop if the ionosphere has the wrong settings and 3G can't get there) I read f-11 Magazine, a free emag which I find has good technical articles in a format I can follow.
They start with the assumption that I don't have any prior knowledge and therefore start with the groundwork and build on that. Means you can pick it up from the point where your knowledge runs out rather than wondering how you get to the point at which they start!
I'm currently working through their flash lighting tutorial with a couple of friends, making it a more enjoyable experience as we learn together.
Some of their photographer profiles are interesting too, though some of the pros work leaves me astonished, most leaves me confused!  :o

Cheers, Graham.

11
Canon General / Re: Does Canon really deserve this?
« on: November 26, 2014, 04:39:41 AM »
Hi Rick.
I'm satisfied with my gear, I am bored with the weather, the DR outside could probably be counted on the fingers of one hand today, thick fog! So currently my gear is more than a match, now the photographer, not so much!  ;D
As for people using their real names, many I believe are using their business names, and many more sign their posts with their real name! I also know that some are using pseudonyms because of their line of work or other sensitivities.
So no you are not the only one posting under your real name, perhaps the only one whose username is their real name.

Cheers, Graham. Real name! (Valvebounce, nickname I've had for 25+ yrs! Many locals would identify me from it)


Yes, yes and don't forget trolls who do not even own Canon equipment.

I may be the only guy posting here under his real name, but for all I know, this could be two dudes in their underwear and their 55 sock puppets each deployed to do battle against each other and one of them started the war with this post.

12
Sports / Re: 17 Year old Sports Photographer
« on: November 25, 2014, 09:10:50 AM »
Hi Charles.
Great set of shots.
On the kneeling thing, try not to, or use very good protection, take it from someone who spent too long kneeling or grovelling around on the ground (when I was young and invincible) in the cold and wet working on cars, if you want to be able to kneel down and stand back up when you are 40 (yes it can be that little time away) without pain and cracking noises, look after yourself! Yes you are young but that is when we do the damage.
Sorry for the dismal nature of my post but you need to not learn these things for yourself.

Cheers, Graham.

I couldn't tell in the football and soccer shots, but are you kneeling or standing?  Getting lower makes high school athletes, especially, look more impressive.  That makes it harder to move around to follow the action, however, but you're young!

Again, great work.

13
Sports / Re: Kayaking
« on: November 25, 2014, 04:35:16 AM »
Hi Climber.
Nice series of shots, unfortunately our Island has no white water, next chance I get will be early next year going back to where I took the shots I started this thread with! (And hoping they are there!)

I really like the second shot, the red one going over the high drop, love the light through the water.

Cheers, Graham.

just to give a bit of life to this topic...

14
Landscape / Re: Mountains, Lakes and Rivers
« on: November 25, 2014, 04:28:11 AM »
Hi dpc.
I prefer the original, I like the foreground rocks, the only bit I was distracted by was the pointy thing far left 1/4 way up the image, kept looking to it to work out what it was.
If it was my image it would still be there too as I don't have the skills or patience to remove just that! :)

Cheers, Graham.

I've decided to remove the rock pile from my previous posting.

15
Canon General / Re: First time shooting a wedding...
« on: November 24, 2014, 06:13:50 PM »
Hi Jd.
I have shot weddings for friends that I knew were already spending way more than they could / should just to try to have a nice day.
I really hate doing weddings due to the pressure to succeed, and the devastation failure would cause!
I concur with Rusty, often "no good deed goes unpunished".
Good luck.

Cheers, Graham.

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