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Messages - Mt Spokane Photography

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4816
Lenses / Re: Smart purchase or not?
« on: November 09, 2012, 12:22:03 PM »
It really depends on the price of the used lens.
Decentered elements cannot be seen, but commonly occur in used zooms, and having it adjusted at Canon might cost you $200-300.  Make sure you allow for that, or negotiate return rights after you test it.  If you are not able to test a used lens, you might not see a definite problem, but may just be unhappy with it and think you selected the wrong lens.  Maybe thats the case for the seller?
A refurb is $671 at Canon, and you can return it if its not right, and has a 90 day warranty.  Canon will likely have a 20% off sale around Black Friday, so a used one with no warranty is worth less than $537 IMHO.

4817
Is it a new computer, or did you upgrade?  Sometimes upgrades cause issues like this, but it should be working on a new installation.

4818
Technical Support / Re: Missing Images from 5D Mark III CF Card
« on: November 08, 2012, 08:54:26 PM »
Usually missing images are a issue with a card reader that does not recognize udma7 or some other incompatability.
Put the CF card in the camera and see if the images are really there.  A number of people have had issues with their card readers and udma 7 cards.  Apparently one of the early usb3 readers had issues and a firmware update fixes it.

4819
Lenses / Re: New 24-70 II, maybe AFMA will help?
« on: November 08, 2012, 08:49:43 PM »
Old Shooter & Mt Spokane:

I have been looking at getting FoCal, my hold up has been that I don't own a tripod and I'm not sure I need one other than for this. Perhaps, it's time to rent one, though :)

Thanks, everyone.

Cheers.

Shawn L.
The purpose of using a tripod is merely to remove the possibility of camera movement as well as making sure that all the test shots are taken from the same place and the same angle.
You might be able to construct something using a 1/4-20 bolt to attach the camera, but it might be more trouble than its worth.
If you can borrow a good tripod and head, that might be ideal.  Sometimes you can find one locally from Craigslist.  If you get a cheap one, hang a weight under the center to stabilize it, a camera bag full of lenses works well.  You can usually screw a hook into the bottom of the center column. 

4820
What I don't get is how this focus shift happens.

Wide open and focussed, all the rays passing through all parts of the lens focus (I think this is a pretty sharp lens?) to a sharp point on the sensor plane.  Occlude some of the rays by stopping down the iris and the unoccluded rays seem to have their paths changed so they focus off the sensor plane.

Don't see how that could happen - maybe there's something different going on.  Can soemone educate me on that?
It occurrs on all lenses, but the construction of the 50mmL and the wide aperture makes it a little more apparent.  You cam mitigate it once you know whats happening and why.
"Focus shift is a displacement of the sharp plane of focus when the lens is focused wide open, but the image is made with            the lens stopped down.
Quite literally, the optimal plane of focus moves, depending on aperture! With every lens I’ve tested to date, the focus moves farther            away. For example, if focus at f/1.4 is centered at 1.00 meters, then by f/2.8 it might now be centered at 1.02 meters. That apparently small            difference means sparkling-sharp eyes versus not-quite-there eyes—it matters, especially with high-resolution digital cameras.
Focus shift is caused by spherical aberration (see vanwalree.com for            an excellent technical discussion). Instead of a sharply-focused point of light a spherically aberrated lens produces a point of            light with a “halo”. This is visually confusing when focusing by eye (because of the lowered contrast) making it difficult to            find optimal focus. It also is confusing to autofocus systems. In spite of these issues, accurate focus can generally be obtained—but            it’s no longer accurate when the lens is stopped down."
http://diglloyd.com/articles/Focus/FocusShift.html
 

4821
Lenses / Re: do image stabilisers decrease image quality?
« on: November 08, 2012, 05:04:33 PM »

 
Yes, something is lost, and it is light. 
But ...  does IQ get worse with each additional element, as he said?  If so, why not a 1 or a 2 element lens?  IQ should be much better than those 22 element lenses - less CA, sharper, less distortion, etc - Really ??  Where are those one or two element lenses with superior IQ, or for that matter, 5 element lenses?
Its a nice theory, but the best lenses with the best IQ have many elements, and they do lose light, but not all that much.  The 9 element 85mm f/1.8 has a Tstop of 2, so it loses 0.2 stops in the glass.  The 20 element 70-200mm f/4L IS has a Tstop of 4.6, so it loses 0.6 stops.  20 elements, and it has suburb IQ and sharpness! 
So, how many elements until you lose a stop?  Maybe 30 some elements?  Your worry that light won't make it thru a lens due to the number of elements seems a bit far fetched.

It is more than just light lost, it is the quality of the light itself, how the light breaks down going through the lens.

It does get worse with each element, because each progressive element corrects one problem and adds another, or not depending. If the lens has 20 elements the last element corrects flaws made through one or more of the previous 19. It will never be perfect and each element takes away, even if it is slightly. There is more lost than just light and loosing a stop, that is why we look for other flaws in our IQ other than just sharpness or quantity of light. No doubt the L lenses deliver great IQ with multiple elements, but it doesn't change that fact that a bit of quality is lost with each element.

A single lens that produces an image with little or no flaw is possible. The human eye has only one lens. Glass and Crystal lenses abilities are flawed in comparison.
I think your theory says it all.  A 20 element lens has lower IQ than a 10 or 7 or 3 or one element lens.
The only problem cones in the FACT that actual measurements disprove it.
 

4822
That is my thought Spokane. I have not ordered one yet, Out of curiosity about how much were they? they came with die-cut adhesive right? thanks for info!

I actually like my 60D's swivelly screen for protection while put-away, I thought I would hate it, but now I can put things in my camera bag more hap-hazardly haha
I bought two of them, one for a 40D that was $15, and one for a 5D MK II that was $30.  The die cut adhesive was a buck or two extra.
I hear that the 5D MK III screen is pretty pricey right now, but the price will drop after 3 years when time comes to sell it.
I've bought used cameras with the after market screens on them.  I could not stand losing the color and contrast thru the cheap screens, and took them off right away.  The more expensive glass screens should be better than those ugly plastic ones that stick on by static electricity and get scratched up almost immediately.

4823
I've seen them discounted already.  They are in stock in most stores too.  They will likely become scarce before Christmas, since many will buy them come black Friday.
Call a dealer (Don't e-mail) and ask for a discount.  You might be suprised.
http://www.canonpricewatch.com/product/03850/Canon-EF-24-70mm-f2.8L-II-USM-price.html

The price in US for this lens is $2300. Where do you see the price drop? The price will remain as is even on black friday(same for 1D X).
It was a short term sale and is over now, I posted a link at the time.
At first, that is the type of sale we will see. 
On Black Friday (or the following Monday) last year, B&H had a blanket 10% discount for all their cameras and lenses.  It only ran for a few hours.  I cannot guarantee that it will happen again, but it is likely. They tweeted it to those who were signed up to receive their tweets.

4824
You are not protecting the LCD screen.  There is already a LCD Screen protector on your camera.
What you are doing is protecting the protector.  I've never seen a need to do that, but have replaced a couple of Canon protectors that had minor scratches after years of use.  I just called Canon and ordered them. 
 

4825
Reviews / Re: Review - Canon EF 24-70 f/2.8L II
« on: November 08, 2012, 12:50:22 PM »
Nice job of reviewing, Justin.  I've had five of the Mark I copies.  None really bad, but not good enough for me to keep them.
I've been watching and reading the reviews, and deliberating if f/2.8 is fast enough for my low light use.  Right now, I use fast primes, and usually find them at f/2 or faster even with extreme high ISO settings.
I did purchase a D800 with 24-70G lens, and found myself at ISO 12800 much of the time, and the D800 requires a ton of NR at 12800.  The images still look good, but I need a supercomputer to do that level of NR on a 150mb image.  I gave up pretty quickly on that idea.
 

4826
Lenses / Re: New 24-70 II, maybe AFMA will help?
« on: November 08, 2012, 12:33:23 PM »
Shawn - I'm not trying to spend your money - but you are shooting a 1DX with a 24-70II... If you like shooting wide open - I would seriously recommend FoCal - it made a huge difference with my 5DIII... If you buy it - after you AFMA - run the aperture sharpness test at both ends... I was really surprised by the results... Cheers!
Yes, first thing to do with a new lens (after you snap a few images just to see it work) is to run a AFMA and FoCal is the best tool, its reliable and accurate (if you read the instructions and follow them)
Then you will know that your lens is focusing accurately.
The other quick and dirty method is to put it on a tripod and use AF to snap a image of a flat target that is parallel to the sensor.  Then use liveview and live autofocus to do the same.  If the live AF image is sharper than the first image, AFMA is needed.
Be aware that its sometimes very difficult to visually detect tiny differences in sharpness, but Focal can detect them, which is why so many use it.
 

4827
Lenses / Re: do image stabilisers decrease image quality?
« on: November 07, 2012, 11:56:12 PM »
Hi,
    IMHO, every element added will decrease IQ by a bit, so a lens without IS will have slightly better IQ than lens with IS (when both lens are from the same generation and same grade) under perfect shooting condition.
So you believe a lens with one element is sharpest?  Maybe one with no elements is the ultimate?

That would be so. Looking through a hollow tube will always give you the clearest sharpest image. You can not improve the light when it is in it's near perfect unrestricted form.
If you believe that, then why buy a lens?  You can get a sharp image without one?  Why don'y you start selling them, you can sell sharper lenses for just the cost of a roll of toilet paper.
Multiple lens elements do, in fact correct the various abberations that come from just one element.  Thats why the lenses that are sharpest have multiple elements.
Your theory seems pretty badly flawed when compared with the real world.

Exactly what do you think lenses do?
They take the pure raw light and the bend it, skew it, rearrange it then focus it.
Multiple elements correct the aberrations that the first few elements create. Multiple elements are used to put the light back in the arrangement it started with. It doesn't improve what is natural.
Without one element the light isn't flawed, it isn't until light hits the glass that it changes and bends and compresses.

Weixing is partially right, in that when it touches the first element something is lost. Every element it touches after it looses something, but the following elements are putting it back in the right order for focus. Put enough elements in a lens the light will never make it through.

Yes, something is lost, and it is light. 
But ...  does IQ get worse with each additional element, as he said?  If so, why not a 1 or a 2 element lens?  IQ should be much better than those 22 element lenses - less CA, sharper, less distortion, etc - Really ??  Where are those one or two element lenses with superior IQ, or for that matter, 5 element lenses?
Its a nice theory, but the best lenses with the best IQ have many elements, and they do lose light, but not all that much.  The 9 element 85mm f/1.8 has a Tstop of 2, so it loses 0.2 stops in the glass.  The 20 element 70-200mm f/4L IS has a Tstop of 4.6, so it loses 0.6 stops.  20 elements, and it has suburb IQ and sharpness! 
So, how many elements until you lose a stop?  Maybe 30 some elements?  Your worry that light won't make it thru a lens due to the number of elements seems a bit far fetched.

4828
Lenses / Re: do image stabilisers decrease image quality?
« on: November 07, 2012, 09:37:27 PM »
Hi,
    IMHO, every element added will decrease IQ by a bit, so a lens without IS will have slightly better IQ than lens with IS (when both lens are from the same generation and same grade) under perfect shooting condition.
So you believe a lens with one element is sharpest?  Maybe one with no elements is the ultimate?

That would be so. Looking through a hollow tube will always give you the clearest sharpest image. You can not improve the light when it is in it's near perfect unrestricted form.
If you believe that, then why buy a lens?  You can get a sharp image without one?  Why don'y you start selling them, you can sell sharper lenses for just the cost of a roll of toilet paper.
Multiple lens elements do, in fact correct the various abberations that come from just one element.  Thats why the lenses that are sharpest have multiple elements.
Your theory seems pretty badly flawed when compared with the real world.

4829
EOS Bodies - For Stills / Re: Would I benefit from going full frame?
« on: November 07, 2012, 09:29:53 PM »
Except for sports or bif, the 5D MK II is a great camera.  I stopped using my 7D except for product photography and macros in favor of the 5D MK II.
If you do low light photography, its a big step.  I am pretty unhappy with the 7D even at ISO 1600 its weak, while I get better images with the MK II at 3200 and even 6400.  I'm hoping to get 1/2 or better additional stops with my new 5D MK III, but I have yet to really give it a heavy duty test.

4830
Lenses / Re: do image stabilisers decrease image quality?
« on: November 07, 2012, 09:18:47 PM »
Hi,
    IMHO, every element added will decrease IQ by a bit, so a lens without IS will have slightly better IQ than lens with IS (when both lens are from the same generation and same grade) under perfect shooting condition.
So you believe a lens with one element is sharpest?  Maybe one with no elements is the ultimate?

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