EOS 70D autofocus tracking???

[Bazsl]

Will the phase detect 19 point AF system in the 70D track subjects moving toward the camera at 100 miles per hour in AI Server mode? In other words, is the 70D usable for still photos of aircraft in flight, horse racing and automobile racing? Any references to articles on the 70D AF sustem that discuss its ability to track subjects moving toward the camera would be appreciated. Thanks.

Bill

[garryjames]

Thanks ebiggs1:  I just bought Lightroom 5 and am looking forward to working with it.  Seems that Adobe has all the CA and spherical aberration values for most all current commercial lenses programmed in.  I'm wondering if that will help.  

I was in the process of fine tuning AF when I read on YouTube that one should shutoff CA, IS and peripheral illumination.  So I did and it seemed to help calibrate.  Then I thought, if one focuses better with these functions off, I'd try shooting without them.  ( the system I was using was EF 300mm F4 IS, canon 1.4x III and 6D.)  I thought I might be able to fix things in post with Lightroom.  Results showed pretty significant chromatic aberration, purple fringes on one side of white herons.  All action shots were pretty blurred.  my keep rate had dropped into the single digits.  I did take some good shots of cranes that were basically stationery.  Then I turned on IS-2 and got one dimensional blur.  I guess from now on I'll shoot IS-1 at least.  

Any recommendatiosn regarding shooting with CA and peripheral illumination off or on?  

Another qustion:  How precise do you tune AF.  I had a hard time seeing differences in focus with changes of 2 clicks on the AF bias.  

With High Regards,

garryjames

[garryjames]

Thanks ebiggs1:  I followed your good example and stopped writing about photograhy and went out and did some.  Yesterday I received the Canon 1.4x III telecoverter.  Last night I calibrated the auto-focus with my the teleconverter, EF 300mm F/4 IS II and Canon 6D body.  Then went out and took pictures of birds.  Here's a shot of a Sand Hill Crane I took this evening...  Hand held from about 30 feet away.   Would like to see what others are shooting.  Happy Shooting.

[garryjames]

Thanks ebiggs1 for your advice regarding tripod and gimbal head.  

I'm doing birding exclusively with a Canon 6D and Cannon EF 300mm F/4.0L IS.

My goal is poster sized (12"x16" Plus) tack sharp prints.

I have several tripods but have not used them for birding yet.  This is due to the fact that I am taking pictures of  stationary birds (relatively speaking) then I try to take flight pictures as they take off.  So I'm doing everything handheld, relying on IS to save me.  I'm getting some decent shots but nothing that can stand up to serious enlargement.  

I am now considering doing stationary shots with the gimbal / tripod as a dedicated session, saving handheld flight shots for a separate session.  I'm going to buy a gimbal head this week, based on your recommendations.  

I'm coming to the conclusion that cropping is killing me.  I count myself lucky if I can get close enough to fill 10% of the area of the frame with the subject.  As such, I'm shopping for a longer lens.  I jsut bought a new Canon 1.4x III teleconverter but know this will not give me what I need, ultimately.  I bought it for flexibility.  The only options i see are:

1)Canon 600mm F/4L II IS   <- at $13,000 this exceeds my budget

Tamron 500mm F/4.5 DG APO (non-IS)   <-  at $5000 is on the upper edge of my budget.

Used Canon 600mm F/4L IS (1st generation IS)   <- at $5,000 to $7000 this is on the upper edge of my budget.

Used Tamron 500mm F/4.5 (non-DG) APO (non-IS)   <-  at $3000 is within my budget.

I think that my preferred option is #3

[garryjames]

Thanks ebiggs1 for your advice regarding tripod and gimbal head.  

I'm doing birding exclusively with a Canon 6D and Cannon EF 300mm F/4.0L IS.

My goal is poster sized (12"x16" Plus) tack sharp prints.

I have several tripods but have not used them for birding yet.  This is due to the fact that I am taking pictures of  stationary birds (relatively speaking) then I try to take flight pictures as they take off.  So I'm doing everything handheld, relying on IS to save me.  I'm getting some decent shots but nothing that can stand up to serious enlargement.  

I am now considering doing stationary shots with the gimbal / tripod as a dedicated session, saving handheld flight shots for a separate session.  I'm going to buy a gimbal head this week, based on your recommendations.  

I'm coming to the conclusion that cropping is killing me.  I count myself lucky if I can get close enough to fill 10% of the area of the frame with the subject.  As such, I'm shopping for a longer lens.  I jsut bought a new Canon 1.4x III teleconverter but know this will not give me what I need, ultimately.  I bought it for flexibility.  The only options i see are:

1)   Canon 600mm F/4L II IS   <- at $13,000 this exceeds my budget

2)   Tamron 500mm F/4.5 DG APO (non-IS)   <-  at $5000 is on the upper edge of my budget.

3)   Used Canon 600mm F/4L IS (1st generation IS)   <- at $5,000 to $7000 this is on the upper edge of my budget.

4)   Used Tamron 500mm F/4.5 (non-DG) APO (non-IS)   <-  at $3000 is within my budget.

I think that my preferred option is #3.  The lens is quite heavy at 190 ounces as compared with 111 ounces for the Canon 500mm F/4 II.  And I'm not sure how good the 1st generation IS is.  If I'm shooting from a tripod I'm not sure it will matter, except that I'll have to carry it to the site.  This will put my pack above 30 pounds.  

[cicopo]

I forgot to mention that for my test I didn't have either a shutter release nor tripod collars for the Nikon lenses, so there's a tiny bit of that softness.

Re not feeling the crop factor is real please explain to me how 2 identical shots through the same lens from the same distance produced two very different pixel counts for the same area of the photo. The 1D4 shot contains 2.33 megapixels while whe 1Ds2 shot (the Full Frame body) only has 1.46 megapixels there. There is only a 4% difference in the files they produce so by moving to either a 1Dx or 5D3 you will still have fewer pixels for the same area I cropped to

5D3 has 22.3 Mpix vs 1Ds2's 16.7, that's a 33% increase so 1.46 X 1.33 = 1.94 megapixels

1Dx is only an 8% increase so 1.46 X 1.08 = 1.58 megapixels.  

[ebiggs1]

Gay James hit the nail on the head. 

Don't get caught up in MP count.

It actually boils down to what the eye sees.  In other words it is the quality of the pixels that is the most important spec.

I am not very good, obiviously, at explaining this.  Although it doesn't seem to deter me from trying.  A few larger pixels are better, more quality light stored in them, than a lot of smaller pixels with less.  And of course you already know larger pixels generally are less noise effected.

[ebiggs1]

Gary James has hit the nail on the head.

Don't get caught up in the MP count.

It actually boils down to what the eye sees.  A few larger pixels stores more quality light than a lot of smaller one do.

We have not even got into noise.  Probably the most important spec.  Larger pixels are less effected by noise than smaller ones.  We won't address resolving power of the lens as we assume the lens is the same for each sensor.  But of course the lens has a great deal more to do with the quality of the photo than anything else.

I am, obiviously, not good at explaining this, however it does not seem to stop me from trying.

[garryjames]

Dear ebiggs1:

Thanks for your post of ‎05-14-2014 09:45 AM.  Your expert opinion is highly appreciated.  

You asked about my budget...  My budget is not fixed.  As with most purchasers, I experience budget creep.  But to sum up my purchasing approach, I am a "Value Purchaser."  I like to find buying opportunities where one can get 80% of the performance for 20% of the price.  That spread might be an extreme example, but it demonstrates the idea.  The 7D and the 70D are within my current budget, but 1D or 5D III are not unless I sell my 6D.

You asked what I own.  Here's what's in my bag right now.

Canon 6D

Canon EF  24-105mm  F/4L IS USM

Canon EF 70-300mm f 4-5.6 IS USM

Canon EF 300mm F/4L IS USM

Canon 1.4x Teleconverter III

I also have some legacy lenses (Adapted to EOS) form my active days about 30 years ago.  Notables include:

Zeiss Distagon 35mm F/1.4

Zeiss Planar 50 F/1.4

Zeiss Planar 85 F/1.4

I also have a handy Sony NEX-3N with a SELP 16-50mm for the car.  

I also just purchased Lightroom 5.

I did consider the Tamron 150-600mm F/5-6.3 but it got mediocre reviews on YouTube (See Tony Northrup)

Am considering the Canon 70-200mm F/2.8L IS USM.

Did consider the Sigma 500mm F/4 for $5000 but it's not IS.

Did consider the Canon 400mm F/5.6 but it's not IS.  (Tony Northrup rates this very highly.) I am hoping to get close to the quality of this lens with the Canon 300mm F/4L IS and a Canon 1.4x III.

The later two lenses would be fine for tripod work but not for birds or planes in flight, unless I get a lot steadier.  

[ebiggs1]

 Here's what's in my bag right now.

Canon 6D

Canon EF  24-105mm  F/4L IS USM

Canon EF 70-300mm f 4-5.6 IS USM

Canon EF 300mm F/4L IS USM

Canon 1.4x Teleconverter III

I also have some legacy lenses (Adapted to EOS) form my active days about 30 years ago.  Notables include:

Zeiss Distagon 35mm F/1.4

Zeiss Planar 50 F/1.4

Zeiss Planar 85 F/1.4

A very impressive bag to say the least.  

I also just purchased Lightroom 5. <---Outstanding!  

"I did consider the Tamron 150-600mm F/5-6.3 but it got mediocre reviews ..."

I have looked this lens over a lot. I have not been able to pull the trigger. The only real thing it has going for it is price.

"Am considering the Canon 70-200mm F/2.8L IS USM."

I will say with out hesitation this is the best 70-200mm made on the planet, bar none.  It can best many primes in it's range.

It is my favorite lens. Along with the 24-70mm f2.8 it is the dream outfit. 

I have been able to try the Sigma 500mm, a used copy, and can say it is very nice.  Well worth the cost.

I have the EF 400mm f5.6 and can easily say it is the best buy in a telephoto.

I have tele converters from the 1.4 to a 3x (various brands). I don't like them at all.  I rarely if ever use one.  But I must say the EF 1.4 on a f2.8 lens works and works well.  Beyond that, not for me. IMHO, of course.

On your EF 300mm f4, the 1.4x III will probably be OK. I have not tried that combo but wouldn't hesitate to.

[garryjames]

Thanks for your response.  Everything you say makes sense.  

There are two limiting factors, lens resolving power / sharpness ( relaize they are different but complementary)  versus the pixel count in the final cropped image.

I guess the question is this:  Which rules, lens resolving power or pixel count as you compare FF with ASP-C?

I've read that the best lenses, and I count the Canon 300mm F/4.0 IS II USM in this group, are capable of resolving 120 to 140 lines per millimeter at a contrast level of 30%.  30% sounds pretty low, but I figure that contrast can be tweaked a bit in post.  So for a full frame cropped to 40%, i.e. Canon APS-C sensor measures 22.2 x 14.8 mm.  if we multiply 130 squared (effective resolved dots per square mm) times the number of square mm's, we get get 5.5 effective megapixels in an APS-C frame, based on lens capabilities.  Compare this with the number of pixels in a cropped FF, which you pointed out is 8 megapixels.  So it appears that the lens limits the resolving power of the system.

The same is true of the APS-C camera, e.g. the Canon 70D.  the lens will give 5.5 megapixels, while the sensor will provide 20.2 megapixels.  Once again the lens is the limiting factor.  The extra pixels are, what I have heard called "empty magnification" as they don't add to the resolving power of the system.

Seems like the only way to get max resolving power is to get a 600mm lens and shoot full frame.  If we calculate the effective pixels for that system (i.e. 130 squared times 35.8 x 23.9mm) we get 14.5 effective megapixels.  Here again we are limited by the resolving power of the lens.  

My question is this, do real world results support this conclusion?  I got a response that using an APS-C body won't give improved results over a FF sensor cropped down to APS-C size.  Yet, there are lots of YouTube videos, Matt Granger and Tony Northrup included, who recommend using APS-C bodies to "extend the reach of lenses."  This contradicts the theoretical calculations above.

Do we know of a quantitative test that addresses this question?