Messages

1

EOS Bodies / Re: How can lens focus ever be "off" in a way that AFMA fixes it?

« on: April 20, 2013, 12:20:49 PM »

It's easy.  You do need a stable tripod, and lots of light in the target (sun or tungsten/halogen, not fluorescent or LED).

Neuro's comment about fluorescent and LED light sources is true for those that are equipped with old-style magnetic ballasts that operate at 60Hz.  The light output fluctuates at 120 Hz and at any shutter speed faster than 1/120 there is a high probability that the image will be captured between peak light levels and the exposure will be incorrect.    Fluorescent and LED lights with electronic ballasts operate at approximately 20,000 Hz, far in excess of any shutter speed you will be using.

2

Third Party Manufacturers / Re: Sigma 85mm f/1.4 DG's odd behavior on 5D3

« on: March 16, 2013, 02:38:11 PM »

I had a similar experience last night.  The Sigma 85mm F1.4 and 5D3 combination would crash every time I would use the Focus Peaking function in the Aperture Sharpness test.  Every Time.

I did NOT have this issue with the Sigma 50mm F1.4.

Sigma 85 serial number:  127xxxxx.

3

EOS Bodies / Re: 7d2 Video specification speculation

« on: March 16, 2013, 01:14:28 PM »

Monitor the sensor temperature when using Live View.  Gets quite hot.  Seems like the same thing would happen during extended video recording.  The rest of the processing components are probably suffering the same fate. 

I never thought that Canon set out to design crippled video features, they just designed the camera for photography and then tested them to see what level of video performance could be achieved without compromising the life of the electronics.  They could have gone the route of allowing higher performance with thermal overload protection, but then the complaints would be about the camera shutting down. 

If they designed the hardware capable of the video some people want, our camera would be as big and expensive as the true video camera.  Probably more expensive, because they would still have to meet our expectations for stills and no video camera does that.  OK, the 1Dc does, but the price of that camera kind of proves the point.

4

EOS Bodies / Re: 7d2 Video specification speculation

« on: March 15, 2013, 09:01:09 PM »

I would guess that the 7D2 video performance will be limited by the same overheating problems that limit all DSLRs.  DSLRs are camera that are designed to take photographs, but happen to have some ability to make video.  The video performance has to be limited to prevent the sensor and electronics from overheating and failing prematurely.

5

EOS Bodies / Re: 7D Mark ii with WiFi/GPS or Without?

« on: February 20, 2013, 01:07:20 PM »

One of the issues with the flip-screen is the amount of space the hinge and frame take up on the back of the camera.  Either we are going to get a much smaller screen or we will lose 5 or 6 buttons on the back.  That is a pretty steep price to pay.

6

EOS Bodies - For Stills / Re: 5d3 and FoCal errors

« on: January 07, 2013, 07:52:20 PM »

Great idea.  I have been saving the csv files along with the PDF files.  When you save a report, a menu pops up and one of the options is to save csv file.  At least there is in the Pro version.

7

EOS Bodies - For Stills / Re: 5D III and 300 2.8 II hit rate for sharp pictures very low

« on: January 07, 2013, 07:43:23 PM »

The AFMA setting is dependent on distance.  If your shot was at a significantly different distance than what you used to make the AFMA adjustment the focus could be visibly wrong.  With a zoom lens not only do you have to account for the change in focal length, you also might have to allow for a change in distance.   

8

EOS Bodies - For Stills / Re: 5d3 and FoCal errors

« on: January 07, 2013, 07:02:26 PM »

Hey Drizzl321, if you do start to test at multiple distances, if you don't mind I would really like to see a summary of the results.  I'm trying to collect enough data to see if there are any patterns to the change in AFMA as the distance changes.  More data from different lenses and cameras would be better.

At some point I will post my results on the CR Forum.

9

EOS Bodies - For Stills / Re: 5d3 and FoCal errors

« on: January 06, 2013, 05:21:04 PM »

This thread has been stagnant for a while, but Drizzt321 asked about my test set up.  I haven’t answered because my 5D3 arrived a few days ago and I’ve been busy shooting the newness off of it.

I have to do my testing at my office after hours or during the weekend.  It’s the only place I have access to with enough space to let me test at 131 feet (40 meters).  When I start with tele-convertors or lenses longer than 200mm I will have to move to the parking garage in the basement.  Besides the available space, the office building has much more rigid floors to minimize vibration, but even so, I sit down and don't move while the tests are running.

I enlarged the standard FoCal 50FL target 2x, 3x and 4x to be appropriate with the 100FL, 150FL and 200FL test distances.  The targets are mounted on pieces of foam-core board, with the center of each target located at the same place on each board.  I made a target stand that lets me quickly change the targets without disturbing the stand or the lights.  After a target change only slight adjustments must be made to where the camera is aimed.
The camera is mounted on a tripod with the legs at their shortest length.  The tripod is anchored using a very taunt bungee cord running from the hook on the tripod to a 40 lb (18.2 kg) weight resting on the floor.

I use two 1000 watt halogen lights to illuminate the target.  These are construction lights so I have to use my Expodisc to correct white balance.  It seems to work OK.  I get between 9.0 and 10.0 EV on the target, depending on how I can arrange the lights.  The office furniture limits me sometimes.  Mostly, I can get between 9.5 and 10.0 EV.

The following is an example of the process I use:

1.   Set up target stand and lights at 16.5 feet (5 meters) from the camera.  This is approximately 200FL for 24mm, 100FL for 50mm and 50FL for 105mm.
2.   Slid 200FL target into stand and run AFMA tests, autofocus consistency test and aperture sharpness test for EF 24 F1.4L II.
3.   Mount EF 24-105 F4.0 on camera and test 24mm focal length.
4.   Change to 50FL target and test 105mm focal length.
5.   Mount Sigma 50 F1.4 on camera, change to 100FL target and run tests.
6.   At this point, if I have enough time I will change the distance and run another series of tests; or if I have another camera body available I will rerun the tests using the second body.

This may all seem like overkill, but I am interested to see if I can find any pattern to how the autofocus setting will vary with a change in distance. 

Also I wonder if some lens manufacturers are optimizing their lens designs to perform well at the standard test distances, but at the cost of performance at other distances.

10

EOS Bodies - For Stills / Re: 5d3 and FoCal errors

« on: January 03, 2013, 10:18:56 PM »

I am in the middle of a long data gathering process using FoCal, 3 Canon bodies and 10 different lens.  I run each autofocus calibration test at least 3 times to assure getting the best setting.  I have found that ocasionally Focal will produce one test with very different results from the others, this happens very rarely but it does happen.  Generally, the results have been very consistent for any camera/lens combination at any particular distance.

I test each camera/lens combination at 4 distances: 50xFL, 100xFL, 150xFL and 200xFL.  This is a lot of testing, but the results from what I thought was a "problem" lens caused me to rigorously test some of my other lenses.  Then my curiosity kicked in, so now it's a project.  The sheer volume of testing has forced me to use a very efficient testing procedure.  The downside of this method is that right now I have a LOT of data, but no complete data for any camera/lens combination.   

The results indicate that depending on the distance there can be a great difference in the calibration setting.  I have an EF 24 F1.4L II when mounted on my 7D is -4 at 50FL, 4 at 100FL and 1 at 150FL.  I have not run the test at 200FL yet.  If I used the setting for the "normal" 50FL I'm sure I would hate this lens if I regularly used it at longer distances.  I have not yet begun to think about what the proper setting for this lens should be.  The bad news is that this is not the only lens that is starting to show this kind of characteristic.  On the other hand, maybe I just have a bunch of bad cameras and lenses.

Part of my motivation for my testing is that I've often wondered why some people will say a lens is fantastic and others will say it is crap.  Maybe, they are just using it at different distances.

11

Street & City / Re: Pictures in DC

« on: November 22, 2012, 06:35:30 PM »

Depends on what you want shoot.  The Jefferson Memorial is good at night.  It can be amazing in the spring with cherry blossoms.  Most of the federal buildings are well illuminated and can be dramatic at night.  Georgetown and the Adams-Morgan area can provide a completely different feel. 

12

Software & Accessories / Re: Luma Cinch Strap

« on: November 19, 2012, 12:47:04 AM »

I have The Cinch on both of my cameras.  One of them replaced a Black Rapid.  A couple of my friends have converted to the Luma strap after they saw mine.

The strap is well made and works as advertised.  I really like how I can snug the camera up close to my body.  It doesn't swing or flop around as I walk or move around.

13

Lenses / Re: 24-105L vs 24-70 Tamron VC

« on: October 29, 2012, 04:55:25 PM »

Some information from Lens Rentals.

http://www.lensrentals.com/blog/2012/09/tamron-24-70-f2-8-vc-issue#more-9153

14

EOS Bodies - For Stills / Re: Canon EOS 5D Mark III Firmware adds HDMI & AF Upgrades

« on: October 23, 2012, 01:28:43 PM »

Canon might be using April 2013 as a conservative estimate.  If they said December 2012 and were a month late there would be an uproar.  When it's scheduled for April and if they deliver in February or March they exceed expectations.

15

EOS Bodies / Re: Canon EOS 7D Mark II Rumors Surface [CR1]

« on: October 08, 2012, 07:52:45 PM »

If Canon do that and price it at $2k then I'll sell my 7D and buy a 7D2, in other words; I'd pay another 500 for those upgrades.

Agreed.  But if the camera is over the $2,000 mark, there had better be some REALLY nice features to justify the price to upgrade.  And I'm not talking about GPS, articulating screen, or touch screen.  In fact, I'd pay money NOT to have the last two "features" on a prosumer SLR.

Why do you hate an articulating screen?  That's one thing I can't understand.  The articulating screen increases your creativity if you know how to use it.  As long as canon can maintain the durability and weather proofing of the camera, articulating screen is great.  At least it's there when you need it.

For me the articulated screen presents two major problems.  First, a Canon style articulated screen means that many of the buttons on the left side of the screen will have to disappear.  The articulated screen uses a lot of area on the back of the camera.  The second is the compromised weatherproofing.  Currently, the the pop-up flash is the main weatherproofing weakness.  I can work around that by sealing the flash with electricans tape when I'm going out
in the weather.  Yes, Canon can try to seal moving parts, but how long will they stay sealed?