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Messages - teedidy

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1
Lenses / Re: Bad Copy of 24-70 f/2.8 II?
« on: October 06, 2013, 10:44:38 PM »
I had the exact same thing with my first copy of this lens. I did return mine and got a better copy the 2nd time.

2
Software & Accessories / Re: And another MagicLantern cool feature
« on: July 16, 2013, 05:41:53 PM »

Interesting, I didn't read far enough for that. I guess it sets the chips to different sensitivities, and then is basically line-skipping and doing the interpolation between them all. Ouch. I think I just hurt my brain trying to think of the math that's needed for some of this.

Skips lines of 2,

RG RG RG RG  -- ISO 1600
GB GB GB GB  -- ISO 1600
rg rg rg rg      -- ISO 100
gb gb gb gb   -- ISO 100
RG RG RG RG  -- ISO 1600
GB GB GB GB  -- ISO 1600
rg rg rg rg      -- ISO 100
gb gb gb gb   -- ISO 100

to avoid funky banding.

3
Software & Accessories / Re: And another MagicLantern cool feature
« on: July 16, 2013, 04:38:14 PM »
Looks like it is only available on the 5DmkIII and 7D due to two separate physical chips to read sensor data with different sensitivity levels. Older cameras only have a single input so this will not be available to all cameras.

4
Technical Support / Re: Canon 5D3 at airshow
« on: July 16, 2013, 07:29:17 AM »
Would useing a polarizing filter ( not sure of the trerm rotated / stopped down ) to cut out as much of the bright sky to get the planes closer to the same exposure as the sky provide any value?

5
Lenses / Re: Canon EF 35mm f/1.4L II Mentioned [CR1]
« on: June 24, 2013, 10:08:51 AM »
I have already saved up for this lens twice! Instead I picked up the 24-70 f/2.8 and the 70-200 f/2.8 IS. Hoping 3rd time is the charm.

6
I am using a Zacuto z-Finder 3.0. I have attached the adhesive mount to a "Vello Snap-On LCD Screen Protector for Canon 5D Mark III"
http://www.bhphotovideo.com/bnh/controller/home?O=orderHistory&A=details&Q=&sku=860349&is=REG The Screen Protector snaps on and off very easily when I know I am only going to shoot stills. Most of the time I leave it on (Can cause partial loss of 100% viewfinder unless you really "squeeze" your eyeball in there).
 I further secure it with a single "Zacuto Z-Bands for the Z-Finder"
http://www.bhphotovideo.com/c/product/657226-REG/Zacuto_Z_BNDS_Z_Bands_for_the_Z_Finder.html

I find this solution works great. I always have my RRS plate attached so most of the mounting plates are not an option for me.


7
Lenses / Re: Canon 24-70 f/2.8L mkii Focus Shift
« on: March 31, 2013, 06:51:26 PM »
HI All,

I have just received my (2nd copy) Canon 24-70 f/2.8 mk II. Being a faithful CR follower and reading http://www.canonrumors.com/tech-articles/how-to-test-a-lens/ I begain from the top and followed ever step I could as best as I could. I also have Reikan Focal and ran through every testing option there was available. What I have found suprised me to the point I originally thought I had received the dreaded bad copy.

There is a definite focus shift on the 24-70 mk II. I have found that from f4 to f5.6 it starts to back focus severely  -5 afma vs +3 afma for f2.8 to f4 and +3 afma f5.8 on.

I am surprised there is not more information already out there on this.
I Found this on a competing forum  http://www.fredmiranda.com/forum/topic/1177402 very similar findings

I understand through research you can hold the DOF button down to get around this issue? But would that reduce effectiveness of the f2.8 cross focus points?

After a quick search it appears the Tamron 24-70 has a very similar focus shift issue. 
http://www.lenstip.com/340.5-Lens_review-Tamron_SP_24-70_mm_f_2.8_Di_VC_USD_Chromatic_and_spherical_aberration.html

Does anyone have any advice? At this point I don't know what to do?

Thank you for your time.

 
Either exchange it again, or send the lens to Canon for adjustment.  I'd say exchange it if you can.  It might have a issue at 70mm.
 
Due to residual spherical aberration,  a lens focus will appear to shift towards the rear, but the 24-70 should do it only very slightly.  For the most part, its just the depth of field that increases more towards the rear as you stop down.
You can decrease the aperture on this photozone chart and see it.
http://www.photozone.de/canon_eos_ff/773-canon2470f28mk2ff?start=1
 
http://toothwalker.org/optics/spherical.html


Thank you for your time on this. After spending a few more days with the lens (and since BH is closed for Passover). I have had some more time for testing. I have (am attempting to) uploaded 2 files both taken at f4 about 78 inches away. The live view has achieved perfect focus and has equal ticks before and after the target. The AF photo is back focused and has its first tick in focus behind the target. Before I return for a second time, I want to confirm this is not normal and I should at least see at least one tick in front of the target in focus.

Looking at the photozone review of this lens there is a focus shift, but their copy has 2 ticks in front and 10 behind at f4, (vs mine has no ticks in front).

As a side note, I really do love this lens. The colors are amazing! Everything at f/2.8 is amazing.
As a secondary side note: when I don't use the center focus point and use one of the f/4 or f/5.6 points, the back focus is not as prevalent. I will try to upload some pics of that too.
 

8
Sedona AZ. 100 miles north. amazing red rock canons. was just there yesterday. will post photos when i get back home. check out the pink jeep tours.

9
Lenses / Re: Canon 24-70 f/2.8L mkii Focus Shift
« on: March 22, 2013, 05:03:56 PM »
Is this normal or is it just the new 24-70?

I've never noticed any shift from other than my 50 L and we all know that has some shift. I also never noticed any shift with any of my 70-200's and I use all lenses up close for 85% of my shots ..

In my testing it is only in the longer end 70mm was the worst, 50mm not as bad but still noticeable. Zero focus shifting at 24mm. I Tested out the 24-105. I was unable to find any focus shift at 70mm.

10
Lenses / Re: Canon 24-70 f/2.8L mkii Focus Shift
« on: March 22, 2013, 04:13:25 PM »
I believe my copy of this lens does the same thing, but I am trying to redo my Reikan test (which produced + numbers -- opposite of expected result) and get time and conditions for a better test. Back focus observed in real-world exposures in which I would not expect last-second movement. But perhaps the same as your lens...

This is my second copy of this lens since I thought the first was a bad copy. I guess if I decide I am going to keep this lens, I need to fully understand what it can and cannot do. I also need to fully understand what I can do to overcome its short comings. I tend to shoot mostly photos around my house with little sticky fingers reaching for the camera. Therefore I tend to shoot a large number of shots inside 3 feet. As long as I keep it at f/2.8 I have no issues, but that will not always be possible.

11
Lenses / Re: Canon 24-70 f/2.8L mkii Focus Shift
« on: March 22, 2013, 02:02:48 PM »
Did you find it only for close shooting distance or in general?
I found it happens to a considerable degree when shooting near MFD. I haven't looked into it much when shooting at greater distances. I suspect it is OK there.


Good point. When I am near MFD  at 5 feet away at f4 the Total Depth of Field is only 1.5 inches ( http://www.cambridgeincolour.com/tutorials/dof-calculator.htm )(Assume 20/20 vision on a 10in print )
This is where I see it, because at twice that distance the total depth of field is 6.2 inchs.


12
Lenses / Re: Canon 24-70 f/2.8L mkii Focus Shift
« on: March 22, 2013, 01:07:35 PM »
I forgot to mention, This only happens at the long end, 70mm. At 24mm there is no issue at all.

13
Lenses / Canon 24-70 f/2.8L mkii Focus Shift
« on: March 22, 2013, 12:22:35 PM »
HI All,

I have just received my (2nd copy) Canon 24-70 f/2.8 mk II. Being a faithful CR follower and reading http://www.canonrumors.com/tech-articles/how-to-test-a-lens/ I begain from the top and followed ever step I could as best as I could. I also have Reikan Focal and ran through every testing option there was available. What I have found suprised me to the point I originally thought I had received the dreaded bad copy.

There is a definite focus shift on the 24-70 mk II. I have found that from f4 to f5.6 it starts to back focus severely  -5 afma vs +3 afma for f2.8 to f4 and +3 afma f5.8 on.

I am surprised there is not more information already out there on this.
I Found this on a competing forum  http://www.fredmiranda.com/forum/topic/1177402 very similar findings

I understand through research you can hold the DOF button down to get around this issue? But would that reduce effectiveness of the f2.8 cross focus points?

After a quick search it appears the Tamron 24-70 has a very similar focus shift issue. 
http://www.lenstip.com/340.5-Lens_review-Tamron_SP_24-70_mm_f_2.8_Di_VC_USD_Chromatic_and_spherical_aberration.html

Does anyone have any advice? At this point I don't know what to do?

Thank you for your time.

14
Lenses / Re: January 8, 2013 Announcements?
« on: January 09, 2013, 01:20:11 PM »
I think, there was a Sigma double agent posing as a Canon rep trying to get everyone excited about a lens announcement. There were two lenses on this date, both by Sigma. Just saying.

15
Lenses / Re: Announcement on January 8, 2013? New Lenses [CR1]
« on: January 08, 2013, 01:48:56 PM »
I see Sigma has Two lenses announced today, did we get duped by sigma into thinking they were Canon's?

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