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Messages - AlanF

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226
Third Party Manufacturers / Re: Tamron 150-600 f/5-6.3 VC Availability
« on: January 16, 2014, 02:16:49 PM »
As this is a variable aperture lens, does anybody know at what focal lengths the aperture changes happen?

I do, and I will be sharing that exact information in my upcoming review (which will be allowed to go live next week).

Why are you holding back such a small snippet of information - it will hardly spoil your review?
maybe it's because he is under nda ?

Dustin
Are you under a non-disclosure agreement or are you just holding back information?

227
Third Party Manufacturers / Re: Tamron 150-600 f/5-6.3 VC Availability
« on: January 16, 2014, 12:46:51 PM »
As this is a variable aperture lens, does anybody know at what focal lengths the aperture changes happen?

I do, and I will be sharing that exact information in my upcoming review (which will be allowed to go live next week).

Why are you holding back such a small snippet of information - it will hardly spoil your review?

228
Lenses / Re: Get a 300mm or 600mm? Oh the agony...
« on: January 13, 2014, 08:18:32 AM »
jrista, that is truly remarkable and shows why a 600 would be nice to have!  And I guess it never ends as something longer is going to give even more detail.  It certainly can be challenging for one to be satisfied with what one has.

Funny, I shot my Grey parrot recently with an extension tube on the 300, allowing about 1/2 closer focus and then I was pixel peeping and wondering why his little eyelash feathers weren't that sharp.  Then tonight I was holding him close and looking at his eye and I couldn't even detect any eyelash feathers.  It caused me to think twice about what kind of resolution I really need to fret about.  Why do I keep doing this to myself when I've already been having so much fun with my 300 and converters.  I guess I'm not alone in this! ;)

Jack

It's not just the lens. The moon is a bit of a specialty of mine...I've spent a lot of time photographing it, and I'm a stickler for excessive sharpness. Also, keep in mind that seeing conditions affect how sharp you can get the moon in the first place. The night I took this shot was EXCEPTIONAL seeing (atmospheric clarity), so I was able to get very good results. Certainly, more focal length helps, but I have managed to get very sharp results at 400mm, 500mm, and 700mm as well. Your 300mm with a 2x TC is more than capable of getting very sharp results...the most important factor, really, is the atmospheric clarity. Poor clarity, and it really doesn't matter what the quality of the lens. Keep at it, use a tripod, manually focus with live view at maximum zoom, and use a shutter release. Make sure you shelter from the wind or shoot on windless nights...and you'll be able to get good results.

Also, I process my moon images to extract the maximum amount of detail. I have a special technique, and I process a certain way to enhance color a bit, exaggerate and attenuate tones to separate different levels of highlight and shadow, etc. That has nothing to do with the lens, and everything to do with knowing your PP software and having an end vision.

Also, you are using a 7D, and it is in situations like these that the extra "reach" of the crop comes into play and beats FF - there is fine detail at the limits of resolution and essentially monochrome.

229
EOS Bodies / Re: Patent: Microadjustment Automated
« on: January 13, 2014, 01:37:57 AM »
Re accuracy of contrast AF detection.
Dual pixel technology is a huge leap forward for this. Live view in the 70D is very fast and the contrast AF spot on. I calibrated my new 70D with both FoCal (very satisfactory) and the sloping ruler method. Live view consistently focussed on the screen with the ruler reading at the correct position. On the other hand, both in Focal and sloping ruler testing, there was the usual spread around the correct focus using phase detect.

Dual pixel technology is much to Canon's credit for both speed and accuracy of contrast detect AF. You would expect from basic statistics that the standard deviation of each reading would improve by the square root of the number of pixels employed in detection.

230
Lenses / Re: Get a 300mm or 600mm? Oh the agony...
« on: January 12, 2014, 05:02:54 PM »
Jack
Here is the moon from my 300mm 2.8 II + 2xTCIII on 5DIII. Hand-held at iso 400, f/5.6 and 1/1000.

231
Lenses / Re: TAMRON SP 150-600mm F/5-6.3 Di VC USD Hitting Market
« on: January 10, 2014, 07:39:03 AM »
A pity that there are no 100% crops in the Chinese link. The measured resolutions are interesting. At 600mm and f/6.3 it's very soft. But, at f/8 it is pretty good and f/11 excellent.

?

There are 100% crops of swans and the model eye.

Anyway, I recall that the initial promotional images were shot at f/9.0 or so. Probably the sweet spot for the 600mm end is around there.

Sorry, I should have said informative 100% crops. There is precious little detail on the swan's face or neck that one can see to judge whether it resolves it. We need to be shown a bird with real plumage, not a blurred whitish.

232
PowerShot / Re: Canon PowerShot SX50 Replacement in the Spring [CR2]
« on: January 10, 2014, 03:39:29 AM »
The current SX50 is a great camera. I would like to see in a new version:
1. Dual pixel technology for faster AF.
2. Larger viewfinder.
3. Touchscreen.
4. Mode dial lock so that my wife doesn't set to self-timer every time she picks it up.
5. An increase in maximum aperture to lower diffraction limitation.


233
Lenses / Re: TAMRON SP 150-600mm F/5-6.3 Di VC USD Hitting Market
« on: January 09, 2014, 03:21:52 PM »
A pity that there are no 100% crops in the Chinese link. The measured resolutions are interesting. At 600mm and f/6.3 it's very soft. But, at f/8 it is pretty good and f/11 excellent.

234
EOS Bodies / Re: Will Canon ditch the AA Filter?
« on: January 09, 2014, 01:38:45 PM »
The image comparisons of the 70d vs. the 6d etc points to the idea that the best of Canon lenses can resolve the difference between the AA filter on the 6d and the smaller pixel size/weaker AA filter on the 70d and heck it looks pretty darn good.

Do you have a link to some images?

235
Lenses / Re: TAMRON SP 150-600mm F/5-6.3 Di VC USD Hitting Market
« on: January 08, 2014, 03:15:10 AM »
Why is there so much fuss about the quality of a $1000 lens that comes with a 5-year guarantee? Buy a copy from a proper retailer and either test it for yourself in the shop or at home if by post and send it back if soft. There are rubbish copies of the 100-400L, but no one makes such a song and dance about it. 

236

Btw (hint, hint :-) ... unless shooting jpeg only use full iso stops, iso 320 is really iso 400 underexposed, iso 640 is iso 800 underexposed, you gain nothing by this but only lose dynamic range.

This often crops up. iso 160, 320, 640 and 1250 are local minima in the jagged profile of noise vs iso for the 5DIII and 7D. Other isos might give you better DR. For what I am doing, I prefer lower noise.

237
Hi there Alan F

I am new to this forum but not new to Canon dslrs and wildlife photography.  I have also just completed a comparison of the two cameras, 70D and 7D.  My experiences were similar to yours in that I found the 70D to have better image quality all around, and focus at least as well, if not with a little more stability, especially when long lenses are used.  I owned a couple of 7D bodies for over a year and have been using the 70D in the field for the last two months.  Here is the link to my comparison:http://www.grantatkinson.com/blog/canon-eos-70d-and-canon-eos-7d-compared

Thanks for posting your kingfisher image, it is a good one
Grant


Grant
Yours is one of the best reviews I have ever seen. Thanks so much for the link. Where my modest contribution overlaps with yours, there is complete agreement, even to the 7D's relative degree of under-exposure. I also learned a few tricks from you.

Welcome to the forum!
Alan

238
You need to download the images to analyse them. My 7D does tend to under-expose and you can see it relative to the 70D.

My take on all of this is that the 70D is superior for my purposes to the 7D. It focusses better, faster and more consistently. I think it is sharper. The noise levels are better. It is a great camera by itself and I think that in good light it will have genuinely longer reach than the 5DIII. The live view focussing is simply awesome.

239
Finally, for the 70D at iso 320, 1/4000 s and f/2.8 (top) and iso 1250, 1/4000 s and f/5.6, the noise levels are still excellent. In bright light, the 70D is not noisy. The same number of photons are hitting the sensor to the noise must be sensor noise, not photons. The quality of the images are excellent, compared with the original.

240
Later on, the sun came out and brightened the room, with dramatic effects on the noise.

At iso160 and 1/3200 s exposure at f/2.8, there is very little noise and the auto exposure was better. The photos of the print are approaching the quality of the original jpeg from the 5DIII.

I should have mentioned that 7D and 70D images are jpegs from RAW with no noise reduction or sharpening, but the original 5DIII image was cleaned up.

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