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 on: August 28, 2014, 05:33:48 PM 
Started by mjperini - Last post by peter45
I would like to read answers too, and related to the 60D.

 on: August 28, 2014, 04:37:05 PM 
Started by Frank Kolwicz - Last post by Frank Kolwicz
I got a call from Canon Pro Services yesterday (I recently signed-up hoping for a better response than previously) and the service tech said that he did see that there was a problem and that the case would be kicked up the chain for a response and that I would hear back tomorrow morning.

In the mean time, I've rented a 500/4LIS(II) and 1.4 extender (III), which I will start using this evening. I got the 500 instead of a 600 because I wanted to see if the loss in magnification would be slight enough to make the easier handling worthwhile with my arthritis and shoulder damage, in case I need to make a purchase decision in the future. It will also give me an easy way to find the images for comparison, if I ever need them, because Canon's exif data does not include the lens serial number, so I can't search for files from the several rental lenses among the archives of my images.

I've also been doing some file editing and gone back to 2012, when I had a good lens, and was well gratified to see how good the images should be!


 on: August 26, 2014, 04:28:19 PM 
Started by Frank Kolwicz - Last post by mjperini
There seems to be quite a hubbub about 70D AF performance on various web locations.  (non- video AF) in my very limited use of video and an STM lens I was very impressed.
As I reported earlier , my Wife used here regular wedding combo of 7D & 17-55 2.8 and 70-200 f/2.8 L IS for 7/8 of the last wedding and switched to the 70D 18-135 stm for the tail end.
There were a lot of unsharp pictures, and AWB seemed all over the lot.
I have not yet had a chance to do any controlled testing, nor have I gone through and set up the most optimal settings for still AF in dim light, with and without flash.
I need to do that, but the still AF in the 70D is very similar to the 7D which has always been a great focusing camera for her.
But I do think SOMETHING is up with the 70D AF, even if it is just that it needs more user attention to setup. I also don't know if the STM lenses need different AF optimization than standard USM.
When I get a chance to do some controlled testing I'll report back if I find anything interesting. I don't want to be critical without doing my homework, but I was taken aback by how different the two cameras performed.  I expected the 70D to be better than the 7D.  It may come down to user / setup  error  (or an 18-135 issue)

 on: August 23, 2014, 11:20:38 PM 
Started by Frank Kolwicz - Last post by Frank Kolwicz
Thanks, Bob,

The 600 on the list is the non-IS model, the one previous to mine, which is the first IS version, so presumably it is compatible.

I'm interested in seeing what an incompatible lens will do on my 70d and I happen to have one, a 1990's era 100-300 f/5.6L. If it is anything notable, I'll send a note.

 on: August 23, 2014, 09:41:02 PM 
Started by Frank Kolwicz - Last post by mjperini
Sorry to hear about the lens problem, and while I'm not qualified to speak to those lens issues ,  I did recently purchase a 70D/18-135 combo for my wife to use as a light weight backup camera to her 7D /70-200 f/2.8 L IS combo  and have noticed a high percentage of slightly soft pictures. I'm currently trying to get to the bottom of that.
In my research I came across the fact that Canon has published a list of lenses that have limited compatibility with the 70D focus system . A 600mm f/4 is on the list. (I'm not sure if that's your lens or not) I also came across a rather technical explanation of 70D AF by Chuck Westfall
Limited Compatibility Lens list:
Chuck Westfall:

I'm not sure if any of this could be part of your problem or not, but I thought I'd pass it along.

 on: August 23, 2014, 08:50:02 AM 
Started by Frank Kolwicz - Last post by Frank Kolwicz
Preliminary note: I still haven't gotten satisfaction from Canon on the repair of my EF600/4L IS(I).

As part of that long on-going quest I recently performed a series of target and field test images for submission to Canon's repair department, including star photos of Polaris and vicinity. All three sets of test images show focus defects due to optical misalignment. The star photos were interpreted by a scientist who specializes in optical imaging for the space program as showing decentering and possibly "wedging" of one or more elements. The terrestrial targets show the inability to produce critical sharpness under the best of conditions. The field shots show wide variation in plane of best focus in AF, both in phase-detect and contrast-detect modes, as well as poor sharpness in the best region.

I hadn't realized this until yesterday, but it seems likely that the erratic and out-of-spec, AF performance I have been getting is most likely due to the optical defect(s) of the lens (I have good performance with a 100-400L, obviously better than the 600).

For my 70d bodies and the f/4 600mm lens,  "Canon specifies the precision of the AF system to be within one depth of focus for a lens’ maximum aperture for standard-precision AF points" (From the Digital Picture article on Microfocus adjustment I wasn't able to find a direct quote from Canon with a Google search.

When a lens's focus degrades, it seems to me that there will be a wider range of almost-in-focus area that probably prevents the AF system from getting a tight fix on the best focus zone and images will show a much greater variation of plane of best focus, further in front and behind the subject - which is what I've been seeing. I didn't understand what was happening before and thought that it was me screwing-up in my technique, despite my years of experience with 600mm lenses and previous ability to get critical sharpness at shutter speeds down to below 1/100th of a second with my current setup when I had a lens that worked properly. There are times when AF is so far off that I get scores, even up to hundreds, of totally out of focus frames in a session, but then I'll get a few that are barely acceptable for small prints and so on, over and over. It's not me, it's the lens, dammit!

 on: August 20, 2014, 09:34:49 AM 
Started by bmpress - Last post by Bob Atkins
That's not something I noticed and not something I've seen many complaints about. I think some people has issues with AI servo focusing using some EOS bodies, but my understanding is that Tamron now have revised the lens firmware to eliminate that.

 on: August 18, 2014, 05:43:24 PM 
Started by bmpress - Last post by peter45
A quick one, know you are busy. Read a review of the Tamron 16-300mm that stated some lens noise came over in the video, and it is not a good video lens. True?

 on: August 17, 2014, 06:06:26 PM 
Started by bmpress - Last post by peter45
Thanks Bob, I hope the move goes well.

 on: August 16, 2014, 10:43:52 PM 
Started by bmpress - Last post by Bob Atkins
I'm sadly a little behind on publishing reviews at the moment. I'm moving house and so I've been really busy over the last couple of months!

I have looked at the Tamron 16-300 and it's much as you'd expect from a lens with that wide of a zoom range (18.8x). There's significant barrel distortion at 16mm which flips to pincushion by 24mm and out to 300mm. Center sharpness is pretty good wide open at 16mm and sharpness holds up as the lens is zoomed, though it does soften slightly at 300mm. Best center/edge performance is at around f8. Corners at 16mm are pretty good, though by 300mm there's again some softening.

Bokeh looks quite nice and the macro magnification is decent at 1:2.9 (15" at the 300mm setting).

It's a little slow since the maximum aperture is f6.3 all the way from around 125mm to 300mm.

If what you want is a single lens to do everything - and you're prepared to compromise slightly in terms of overall sharpness and lens speed - then the Tamron 16-300 is a good choice. It has the widest range you can get and it's certainly optically good enough for typical amateur use. It can't compete with a bag of prime lenses of course, but you wouldn't expect it to.

At $629 it's not cheap and a lens like the Tamron 70-300/4-5.6 is better and cheaper at $449 (and it's one of my favorite lenses), but of course it doesn't have the wide zoom range of the 16-300 and it's bigger and heavier - which is why I'm sure that many people will go for the 16-300.

Tamron 16-300 at Adorama

Tamron 16-300 at Amazon

Tamron 70-300 at Adorama

Tamron 70-300 at Amazon

I hope I'll have time to write up a more complete review soon - but I'm still spending most of my time sorting out my stuff and packing it into boxes ready for the move!

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