December 21, 2014, 02:54:10 PM

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### Messages - serendipidy

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31
##### EOS Bodies - For Stills / Re: POLL: What's more important, gps or wifi?
« on: September 21, 2014, 11:52:59 PM »

This subject reminds me of the riddle in the movie, "Roxanne":

"What can you sit on, sleep on, and brush your teeth with?"

a) A chair, a bed, and a toothbrush.

My guess was water

32
##### Lenses / Re: Do you keep all your boxes?
« on: September 21, 2014, 11:17:43 PM »
I have purchased used lenses that did not include a box,... and then I purchased a used box.

Great idea! I keep all my boxes...maybe I could sell them to those who threw them away.

33
##### EOS Bodies / Re: 5diii to 7dii?
« on: September 18, 2014, 04:15:41 PM »

34
##### EOS Bodies / Re: 5diii to 7dii?
« on: September 18, 2014, 04:15:07 PM »
I think you would miss FF quality...  or FF feel... or that FF what ever. That Je ne se Qui (I failed French in HS)

C'est la vie

35
##### Technical Support / Re: 5D III OR 6D or 7DII
« on: September 18, 2014, 04:13:13 AM »
I remember this from ALAN F comparing actual reach of crop vs FF...it's not 1.6 times better as I always thought.

Here is a way of calculating the effective extra reach or resolving power of a crop body versus FF, which will amuse the geeks among us.

Measure the MTF of a lens on the crop (= MTFcrop) and the same lens on the FF (= MTFff). The ratio of the MTFs, MTFcrop/MTFff, gives the relative resolving power of the bodies with that lens. However, the crop body can be placed 1.6x further away to give the same field of view. Therefore, the true effective relative resolving power, R, is given by:

R = 1.6x MTFcrop/MTFff.

Photozone lists measured MTFs for a set of lenses on the 5DII and 50D. I calculated their ratios for the Canon 200mm f/2.8 II, 85mm f/1.2 II and 35mm f/2 at wide apertures below the DLA. MTFcrop/MTFff is very close to 0.726 in all cases.

This gives R for 50D/5DII = 1.16.

So the effective extra reach is 16%.  (Based on the ratio of their pixel sizes, a value of 36% is expected.

The dpreview widget gives values for the 5DIII and 7D only for a few lenses. I did the same calculations with the Tamron 150-600mm (between 150-400mm), the Canon 200-400mm and the Sigma 50mm f/1.4 A at wider apertures below the DLA. In all cases, MTFcrop/MTFff is close to 0.742.

This gives R for 7D/5DIII = 1.19.

So, the effective extra reach is 19%. (Based on the ratio of their pixel sizes, a value of 45% is expected).

There are always arguments about using MTFs quantitatively, but I think in this particular calculation it is reasonably valid to use them. It fits in reasonably well with experience - Jon has shown there is better resolving power in photos of the moon with the 7D, but it doesn't look 45% better. And my own experience is that the 7D and 70D aren't much better than the 5DIII, certainly not 1.6x.

This gives R for 7D/5DIII = 1.19.

So, the effective extra reach is 19%. (Based on the ratio of their pixel sizes, a value of 45% is expected).

That might be true in a testing scenario, but few of us shoot in those. Factor in AF, handholding, higher than base iso, less than ideal aperture or shutter speed etc etc etc and the differences become minimal, as so many people who have owned both have attested to.

As I've stated, the most significant advantage to APS-C is lower cost.

36
##### Technical Support / Re: 5D III OR 6D or 7DII
« on: September 18, 2014, 04:04:07 AM »
I may be misquoting him but I think Neuro often says the main advantage of crop vs FF is that the crop camera is cheaper. Also cropping 5D3 FF to 7D crop sensor size is very similar except now you have a 8MP file instead of a 18 MP file (for the 7D).

Well, idea is, if you have a bottomless pit of money with full frame you can just buy a longer lens and get better results than crop with a shorter lens.  But, the OP has a 100-400 and shoots wildlife; the FOV at 400mm on his current camera is ~640mm.  In order to get that on full frame he'd have to spend \$10k on a Canon EF 600mm f/4L or start putting on teleconverters which will negatively impact the image quality (and often autofocus) more than a crop camera will.

So yeah crop is cheaper, but its not just the camera but more importantly the lens when you get to longer focal lengths.

As for cropping full frame to APS-C, when you are reach limited there will be more pixels on the target with crop.  Cropping full frame will work but you will lose detail because of this.  The exception to this rule would be when shooting in low light (i.e. ISO6400) when the lower noise & higher contrast of full frame would likely be a better tradeoff for a little less detail.  Some feel that cropping full frame is at worst no difference but that is not my experience at lower ISOs and it does not logically make sense to me knowing how digital imaging works.

jrista did a fairly well controlled test here that can demonstrate the loss of detail when cropping full frame vs using a crop camera on a reach limited target for a visual demonstration; you can see in his test the full frame crop loses a ton of detail on the moon surface/craters because there just aren't enough pixels to fully reproduce it on full frame due to the cropping:
http://www.canonrumors.com/forum/index.php?topic=22161.0

Thanks, Ruined for your reply. As an old guy newbie hobbyist, I don't understand a lot of this technical stuff. I looked at your link to jrista's moon shot comparison and that actually is where I got  the Neuro quote reference.
Thanks for the comparison!

As I've often stated, APS-C does have a 'reach advantage'...if you're FL limited AND at low ISO (~800 or less) AND printing larger than 16x24"/A2.

Something else I'm curious about...how small is too small?  For your moon shots, would a 16-18 MP m4/3 body via adapter yield more detail than your 7D?   How about an SX50 HS (granted, not the same lens - but AlanF has posted some provocative comparisons).

Moon shots aside, I'm not convinced of the advantages for bird photography, for several reasons.  If I'd need to crop an image too deeply, I would just delete the shot (more likely, not have taken it).  With the shutter speeds needed, ISO often needs to be raised beyond the tipping point, where the greater noise of APS-C means less detail.  Those are sensor-based factors, and as I've also often stated, we don't take pictures with bare silicon sensors.  Many people have reported that the AF of the 5DIII yields a higher keeper rate than the 7D, and a higher keeper yield of in-focus shots despite the lower frame rate (and with the 1D X, both rate and yield are higher).

I appreciate the careful testing in the specific situation you describe.  I'd be very interested to hear, after you've used the 5DIII to shoot birds for a while, how frequently you grab the 7D for that purpose, instead.   Like Skulker, I kept my 7D for a while...and didn't use it, so eventually sold it (and for far more than it would fetch today, with 7D prices dropping like a stone).

Despite the 'reach advantage' held by APS-C in certain specific scenarios, IMO the main advantage of APS-C is not reach, but lower cost.

37
##### Technical Support / Re: 5D III OR 6D or 7DII
« on: September 17, 2014, 05:07:10 AM »
Quote from: colin.davis on Today at 01:03:18 PM

"Ruined: You are a smart person. I like smart people.  Thanks for coming to the forum  I am going to go out and do a photoshoot at 250 and see if I can tolerate it... This might be a diccy (& fight provoking) question, but, how much could you 'crop' a full frame image to say it is the 'same' quality as a crop. Rather than 250, could it maybe closer to 300/320?  oh god my brain hurts and I'm not even trying to work out the answer.  I guess there are probably many variables..."

I may be misquoting him but I think Neuro often says the main advantage of crop vs FF is that the crop camera is cheaper. Also cropping 5D3 FF to 7D crop sensor size is very similar except now you have a 8MP file instead of a 18 MP file (for the 7D).

38
##### Lenses / Re: Lenses that you want Canon to release next
« on: September 17, 2014, 03:29:05 AM »
100-400L IS USM II

39
##### Lenses / Re: 100-400mm and more DO lenses confirmed
« on: September 17, 2014, 03:25:18 AM »
Dolina I think the conflation was directed to s rock's comment as you separated the propositions with a conjunction.

The conjunction was a correction of the corrigendum, as the conflation was contained in the communique at its creation.

Ahhh...a consonant alliteration

40
##### Lenses / Re: When will we see a replacement for the 100-400?
« on: September 10, 2014, 04:08:18 AM »
Help us Obi-Wan Kenobi. You're our only hope.

41
##### EOS Bodies / Re: EOS 7D Mark II & Photokina
« on: August 29, 2014, 05:16:12 AM »
The problem with the basic laws of physics is that our understanding of them has always been incomplete. They still are.

42
##### Photography Technique / Re: APOLLO missions - image inconsistencies
« on: August 18, 2014, 05:36:48 AM »
and as has been posted before..... proof that it was faked because if you look carefully in the left hand corner of the picture, you can see a housecat...

I was wondering where my cat went! Lost him shortly before Apollo 11 lifted off.

He went Hollywood...

LOL...good for him. At least someone in our family made it big

43
##### Photography Technique / Re: APOLLO missions - image inconsistencies
« on: August 17, 2014, 10:16:00 PM »
and as has been posted before..... proof that it was faked because if you look carefully in the left hand corner of the picture, you can see a housecat...

I was wondering where my cat went! Lost him shortly before Apollo 11 lifted off.

44
##### Animal Kingdom / Re: Your best animal shots!
« on: August 16, 2014, 04:35:24 PM »
dpc...Really great series of photos! Excellent work.

45
##### Animal Kingdom / Re: Show your Bird Portraits
« on: August 13, 2014, 04:51:30 PM »
Hello,
this is my first post on the forum...
Here's a young swan from two months ago. Quite a boring and over-shot species but a picture that I am personally happy with.

Gorgeous.
Welcome to CR.

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