Canon 4x zoom lens

[john-henry]

Got my hands on a A570IS today, 4x zoom so expected vignetting problems as with the A620 etc. not so, no problems at all, the vignetting was no worse than other cameras I've tried with 3x zooms, including Nikon, Fuji, Sony, Olympus etc.
Using it on a Zeiss 85 with 20-60 zoom at 20x vignetting disappeared at 3 steps of the camera zoom and at 30x 4 steps on the camera (there are 7 steps altogether), vignetting all clear up to 60x with both then.

Canon must have changed the design of the lens although it still has a 35 - 140mm range, this could be great news for digiscopers because it opens up the canon range with this lens again.
Anyone using Canon A500 series, or other canons, finding the same thing with the 4x lens?

The 570IS is a very good price at the moment £100-110 in several places, worth a look if anyone wants a new camera.

I'll post a bit more info when I get a chance to give it a good try-out, and we get some half decent weather 3:-)

Regards

John

[Neil]

John,
That's interesting news. It is a different lens ( 2.8 - 4.1 v 2.8 - 5.5 ) so not as fast. It's also not as sharp as the A640 or even the A620 (DPReview). How is the screen for focusing and reviewing out in the field?
I'm looking forward to seeing some test images, Neil.

[macshark]

A 570 IS has a smaller sensor than A620, this may be one reason why vignetting is less prominent.

[john-henry]

John,
That's interesting news. It is a different lens ( 2.8 - 4.1 v 2.8 - 5.5 ) so not as fast. It's also not as sharp as the A640 or even the A620 (DPReview). How is the screen for focusing and reviewing out in the field?
I'm looking forward to seeing some test images, Neil.

Neil,
I've just had a trawl through the Canon range on DPReview, it seems all the 5** range have this lens - 35-140, F2.6-5.5 (it's actually faster at zero zoom) and the 6** range have a 35-140 with F2.8-4.1 (faster at full zoom), from their zoom operation it's obvious there is some difference in the lenses apart from aperture range - I wonder why they messed up the 6** range for digiscoping when they already had a 4x lens that would have put their cameras as one of the top favourites with digiscopers the world over!!!
I'm wondering if your 640 has 7 steps of zoom like the 570, maybe there's some difference there.

Looking at DPReview again there's very little difference in the resolution tests between the 620 and the 570 (1550, 1600, +1000) and (1550, 1500, +1000) so it shouldn't be too bad, when we get some decent weather over here I'll get out and give it a good going through, at the moment it's all high winds and dull, grey skies.

Re the screen, it's certainly low res. 2.5" with 115,000pix so no good for focusing only composition. A few of other niggles are no 'C' mode, camera always defaults to Evaluative metering and Single drive, it's no great problem as both can be set in seconds via the FUNC button, it does hold the rest of the FUNC settings and all the MENU settings though.

On the positive side noise control seems quite good at ISO 200, autofocus is fast and accurate and the few shots I've taken indoors show lots of detail.

Cheers for now

John

[Neil]

John,
Sorry I mis-read the A570's wide f2.6. That will be useful for digiscoping.
Though I can't understand how the Canon's sell so well with such poor screens. The Fuji F31/F50fds also don't have a C mode and revert to Single Shot every time you review or switch off. Very annoying.
If the lens is more "digiscoping friendly" then the A600s then they might work with zooms which would be a boon. I also like to use one with my Swaro 45x fixed.
Looking forward to seeing the results, Neil.
ps also check the use of Macro with Digiscoping.

[john-henry]

Neil,
Managed to get out for a little while today and grab a few shots, blowing a gale but some sunshine, I've posted a few shots below to give some idea of lens quality, seems pretty good to me, both in sunlight and dull conditions at 100 ISO, didn't get a chance to give it a good workout but so far quite pleased with the results, will try it at 200 ISO next chance I get.
Couple of other things worth knowing is the tripod bush is not in the centre but at the left hand side (like the Fuji F30) and I'm finding it needs high rated NiMH rechargeable batteries, battery life is poor with 2400mAh but pretty good with 2600.
The camera itself is quite user friendly, if you've used an A series before you know where and what everything is.

I presume you can get the EXIF data off the pics if not let me know and I'll post it.

All I've done is basic Levels, USM and cropped them to 7"x5" to try and show detail then 'save for web'.

First impressions are it's a nice little camera, especially at the price, for digiscoping.

Cheers

John

PS having a lot of trouble with Birdforun tonight, keeps losing the site.

[Feathered one]

You had some sunshine down there today John.
Particularly good pictures of the Grey Squirrel, not that I like Grey Squirrells.

The exif doesn't show on the pictures, I am sorry to say. Probably due to you using "Save for Web"

Look forward to more pictures.

Regards

Malc

[Neil]

[QUOTE=john-henry;1106253]Neil,
Managed to get out for a little while today and grab a few shots, blowing a gale but some sunshine, I've posted a few shots below to give some idea of lens quality, seems pretty good to me, both in sunlight and dull conditions at 100 ISO, didn't get a chance to give it a good workout but so far quite pleased with the results, will try it at 200 ISO next chance I get.

John,
These look very promising. No hint of vignetting/shadowing around the edges and nice sharpness. I ran the squirrel through CS2 ( no Exif ) and it will even sharpen up a bit more. Very nice.
Does the camera have Digital Enhancement for Manual Focusing and the Programmable Self-timer? If so I need to get one.
Neil.

[ostling41]

I see the A570 IS can mount this lens adapter http://www.bhphotovideo.com/c/product/491233-REG/Canon_1908B001_LA_DC52G_Lens_Adapter.html . That could facilitate coupling it to an eyepiece with a simple dual-diameter collar (which I can machine out of Delrin). How does this LA-DC52G adapter attach to the camera body? I don't see bayonet fittings. Is it a simple press fit over the lens barrel?

[David142]

The LA-DC52G fits as other Powershot cameras . Remove the outer ring and adapter bayonets on . I have an eyepiece adapter with a 52 thread which screws straight into the LA-DC52G.

[john-henry]

Neil,
Yes it has the programmable timer, 1-30 secs with 1-10 shots, easily accessed via the FUNC button and yes it also has the magnified central viewing portion in MF.
I had a longer look at yesterdays pics today, very little CA/purple fringing even at 200%, some NR is being done in-camera, artefacts can be seen in the background at 200% but detail is still being held very well, i'm quite impressed really for such a budget camera.

Regards

John

[john-henry]

You had some sunshine down there today John.
Particularly good pictures of the Grey Squirrel, not that I like Grey Squirrells.

The exif doesn't show on the pictures, I am sorry to say. Probably due to you using "Save for Web"

Look forward to more pictures.

Regards

Malc

Yes Malc, some sunshine at last, even if it was only for a couple of hours then back to grey, gloomy skies. Today is all rain, low cloud again.
Like you I'm not fond of Grey Tree-rats but they're easy subjects for testing.

EXIF data:
They were all taken at ISO 100, Auto WB and 7.9mm camera zoom with 20-60 zoom eyepiece set between 20 and 30x. (7.9mm clears vignetting at 20x).

0111 - 1/250th@f3.2, CW metering, -0.67EV (cloudy)
0112 - 1/200th@f3.2, CW metering, -0.67EV (in shade)
0114 - 1/640th@f3.2, CW metering, -0.67EV (sunny)
0126 - 1/50th@f3.2, spot metering,-0.33EV (cloudy)

Best wishes

John

[ostling41]

it also has the magnified central viewing portion in MF.


John,

Do you use the camera in Manual Focus mode, focusing with the scope? If so, does the magnified central viewing function makes this easy to judge.

What is your adapter set-up?

[john-henry]

John,

Do you use the camera in Manual Focus mode, focusing with the scope? If so, does the magnified central viewing function makes this easy to judge.

What is your adapter set-up?

Allen, I'm normally happy with the Autofocus on most digicams, focusing the scope as accurately as I can first.
I only use MF if there are obstacles in the way of the bird then I do use the magnified central portion and yes it does help especially if you zoom the camera up as well to 'tweak' the scope then zoom it back to where you want to take the picture.

I use a home made swing out adapter.

Regards

John