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Messages - drmikeinpdx

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91
Lenses / Re: Focus Issues with EF 24-70mm 2.8 usm
« on: July 19, 2013, 12:11:41 PM »
LensRentals.com had a good article on these lenses:

http://www.lensrentals.com/blog/2011/10/the-limits-of-variation

I never bought this lens because my Tamron 28-75 was doing the job for me.  I did rent one from Lens Rentals to see what I was missing and it had absolutely horrible focus shift as you zoomed through the range.  I assume that copy was worn out as described in the article above.

92
Lenses / Tamron 28-75 2.8 non-stabilized
« on: July 19, 2013, 12:04:38 PM »
Tamron 28-75 2.8

Agreed, this is a great lens for someone who has switched to full frame, but doesn't have the budget for L lenses.  I keep mine around for backup.

I also have a friend who shoots lots and lots of people pix with this lens on a 7D.   Its a nice portrait lens on a crop body. :)

93
Third Party Manufacturers / Sigma Service :)
« on: July 18, 2013, 09:34:46 PM »
Like a lot of photographers who use 50mm F/1.4 primes, I often wonder if it could be a little sharper wide open or focus a little more accurately.  While I was getting to know my new 24-105 L zoom last month, I decided to send my Sigma 50/1.4 in to Sigma for a little TLC under warranty.  I've had it for about two years.

On the repair request, I said that it was not as sharp as I wanted wide open and it did not focus as accurately as my Canon lenses.  I figured that would challenge them a little.

I got the lens back exactly two weeks after I sent it, which means they had it in the shop about 3 working days, by my estimate.  Pretty impressive.

The service invoice says they "adjusted af data"

If there is any improvement in performance, my methods are not adequate to detect it, but I do feel better knowing that the lens is properly calibrated. It's a confidence thing, you know.

This is still one of my favorite lenses, along with the Canon 85mm F/1.8.

94
Pricewatch Deals / Re: Super Deal: Canon EOS 5D Mark III Body $2545
« on: July 18, 2013, 12:15:19 PM »
If you've been waiting, I'd say jump now!

95
5D MK III Sample Images / Re: Model Study with Nude - 5D MKIII
« on: July 18, 2013, 12:03:26 AM »
I liked this topic so much, I took my 5D3 out for a little nude photoshoot with my old Sigma 50mm and here is what I shot:



I know you can't tell for sure, but I swear the horse wasn't wearing anything!

BTW, that was at F/1.4, ISO 100, 1/400.  The Sigma/5D3 combo does not give the most precise autofocus, but it is quite usable, especially in good light.

96
Canon EF Prime Lenses / Re: Canon EF135mm f/2L USM
« on: July 09, 2013, 11:47:13 PM »
Most of my work is too naughty for this forum, but I really wanted to contribute to the 135mm thread.  I really love this lens.

Here is a test shot from a recent photoshoot, taken while I was dialing in the exposure.  It was processed in Lightroom with the default settings, except for max sharpening on export.

info: 5D3, 1/1600 sec, ISO 100, F 2.2



And here is a crop from the center.  I'd show a corner crop, but I always let the corners blur.  I've come to realize that corner sharpness is irrelevant to the type of shooting I do.




97
EOS Bodies / Re: So I made the jump to FF - now what?
« on: July 07, 2013, 11:42:52 PM »
JPAZ makes a good point about the ability to crop full frame images.  I'd add that it works best if you have a sharp lens. 

I got a 24-105 to use on my 5D3 about a month ago and I'm still getting used to it.  Today I cropped a tiny area out of an image to post online and was truly impressed with the quality.

Discussions like this one are mostly for fun, but I'll toss in my thoughts.  I shoot mostly people.  If my only lens was the 24-105, I'd start getting some prime lenses to use at wide apertures and separate the subject from the background.  Any primes in the range from 50 to about 135 are very useful for this, and in fact that is where I have concentrated my prime purchases.  The 135 L is a great people lens and could be used for sports with a bit of cropping.  Its also not terribly expensive. 

98
EOS Bodies - For Stills / Re: Canon 40D to 5D Classic. Good upgrade?
« on: June 30, 2013, 12:55:25 AM »
I used to use a 5D/40D pairing but replaced them last year with a 5D3/7D pairing.

Same here.  I'll say that once I got the 5D, my 40D got very little use.  I basically kept it around as a backup body and for any situation that required fast shooting, like sports.  Unfortunately, I never shoot sports!  I really did not get my money's worth out of that 40D.

Even after I got the 7D, the 5D classic was still my preferred camera until I was able to buy a 5D3.  I hope to keep the Mark 3 forever. :)

I complained a lot about the crappy autofocus on the 5Dc.  It was inconsistent and lacked AMFA.  Drove me crazy trying to do shallow DOF shots with fast, non-L primes.  If you generally used something like a 24-105, that would not be an issue. 

99
Canon EF Zoom Lenses / Re: Canon EF24-105mm f/4L IS USM
« on: June 29, 2013, 08:27:25 PM »
Went to the hot rod show today and used the 24-105 as a walking around lens.  I added a lot vignetting in Lightroom. :)

This was at F/4.5, 55mm, ISO 100, 1/320 using the 5D3.


100
Pricewatch Deals / Re: Deal: Canon EF 24-105 f/4L IS $699
« on: June 28, 2013, 09:20:08 PM »
I got one from BigValue.com for $725 a few weeks ago.  It came in a white box instead of the usual red and white Canon box.  It came with a USA warranty card and I entered the serial number into the Canon online registration system with no problem.  The lens works great!

I'm guessing that these cheap lenses come from kits that were broken up by the retailer.

$699 is a great price!  I feel sorry for the guys trying to sell theirs on Craigslist for $800 or more.

101
Software & Accessories / Re: Lightroom Help?
« on: June 28, 2013, 12:21:21 PM »
Lightroom does have a pretty steep learning curve, in my opinion, although not as bad as Photoshop!  You do need plenty of learning help.

I prefer to have a book at hand when I'm working on my PC, rather than videos.

I really liked "Lightroom 3, the missing FAQ" by Victoria Bampton.  I bought it cheap at a local used bookstore after Lightroom 4 came out and it really helped me a lot, especially understanding how to set up the catalog and other file related tasks.  Using the retouching and adjustment tools I found pretty intuitive, but I did look up a few helpful hints.

There is a new version for Lightroom 5:

http://www.lightroomqueen.com/books/adobe-lightroom-5-missing-faq/

102
EOS Bodies - For Stills / Quick and dirty low light focus test
« on: June 26, 2013, 01:27:04 PM »
OK, I took my 5D3 and four lenses into my studio and reduced the ambient light to the point that the lenses were just barely able to focus.  I varied the light a little bit to sort of bracket the point at which each lens would begin to focus. 

I aimed each lens at my usual focus grid target placed flat on the floor. The grid is essentially a ~ 3x5 foot piece of white graph paper with 1 inch squares.  It is actually a cardboard layout mat for sewing projects. The focus point consisted of a 12 inch length of black tape across the center of the grid so it was a fairly high contrast target.  I stood about ten feet from the focus point and aimed down at about a 30 degree angle.  This is the setup I use for MFA, although I normally let the camera have a lot more light to focus.

The actual exposure was made with a strobe to eliminate camera shake.

My results:


24-105  F/4:  needed the most light to focus, but focused accurately when focus lock was achieved.  The target appeared dim in the viewfinder and it was sometimes hard to find the black tape focus target.

Tamron 28-75 F/2.8:  needed moderate light to focus, accuracy was acceptable, but not as precise as the Canon lenses.

Canon 40mm F2/8:  needed moderate light to focus, but very good accuracy

Canon 85mm F/1.8:  needed the least amount of light to focus and had extremely good accuracy.

As always, your mileage will certainly vary!

103
More reliable source:
http://www.the-digital-picture.com/photography-tips/Canon-EOS-DSLR-Autofocus-Explained.aspx

I knew I could do better than wikipedia ;-)


Thanks, that's a great article!  I now have a better understanding of how the system works. :)

I think I'll still want to do some low light focus tests with my available lenses.  The author emphasizes the importance of using lenses with a max aperture of 2.8 or wider, but that's not the whole story.  I'll put on my geek hat and head to my studio!  Oh, and I'll include the 40 pancake in the tests.

104

Um? The AF system gets its light through the lens just like anything else... and the camera AFs with the lens wide open. The reason the AF system is dealing with so much less light is that it only gets the fraction of the light that comes through the mirror; anything reflected to the viewfinder can't be used for AF. So, a wider max aperture does provide more light- both to the viewfinder and the AF system...

bseitz234, that doesn't sound like the system used on current Canon DSLRs as I understand it.  To clarify, I'm talking about the phase detection system that uses an array of sensors in the viewfinder area.  This system only does its job when the mirror is down and all the light coming through the lens is reflected up into the viewfinder.  You may be thinking of cameras that use a partially silvered mirror which splits the light between the viewfinder and the image sensor?

Or perhaps you are thinking about the contrast detection system that operates in live view mode?  Let's save that for another discussion. :)

105

The important part about the aperture: the AF-system has its own, and that is always stopped down quite a bit, so anything wider them f/16 or so has no effect on the amount of light the AF gets.

Thanks Lawliet, that's very interesting - just what I was wondering about. That would appear to suggest that selecting a lens with an aperture larger than F/2.8 will not provide any additional advantage for autofocus speed/accuracy.

Can you tell me more about where this autofocus-specific aperture is located?  Does each focus sensor have its own?

Thanks!

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