A620 vignetting

[john-henry]

I'm seriously thinking of upgrading from the A95 to the A620 but the question of vignetting keeps bothering me.
Is anyone using the A620 with a Zeiss 85 scope, if so what sort of results are you getting with the 20-60 zoom at 20x and 30x?.
On the camera specs it shouldn't be too bad but it depends on the movement of the lens and how close it can be set to the scope eyepiece, does anyone know how similar the movement is compared to the A95?.
Apart from the vignetting problem? this camera would seem to be ideal for digiscoping having virtually all the other requirements needed.

I'd like to hear comments from anyone using this camera, with any scope and any adapter, and perhaps we can come to some conclusion on what is going to be a good lens for digiscoping and what is not, considering their very small differences in focal length, for example the A95 is 38-114mm the A620 35-140mm, 3mm difference at the lower end but what a difference it makes.

I've found through personal use the A95, CP 995 and 4500 all start at 38mm and with a Swarovski AT80HD + 20-60 zoom eyepiece vignetting disappears at about the same camera zoom level, roughly halfway, above this there is no vigneting at any scope magnification camera zoom levels. The Zeiss is a little better, losing vignetting at a slightly lower camera magnification, probably due to having a larger diameter exit pupil.

Looking forward to your comments,

John

[mmdnje]

Hi John. I just took a look at the A620 yesterday. There is so much excursion of the lens during zooming that I do not think will work well for digiscoping. I was thinking that using the lens adapter it would be easy to connect to my pentax xw20 eyepiece, but there is so much variation in lens-eyepiece distance during zooming that i do not it will work. The difference in camera lens position is ~1.1cm going from Wide angle to Telefoto and that is too much for me. In summary I did not like it. Jose.

[john-henry]

Hi John. I just took a look at the A620 yesterday. There is so much excursion of the lens during zooming that I do not think will work well for digiscoping. I was thinking that using the lens adapter it would be easy to connect to my pentax xw20 eyepiece, but there is so much variation in lens-eyepiece distance during zooming that i do not it will work. The difference in camera lens position is ~1.1cm going from Wide angle to Telefoto and that is too much for me. In summary I did not like it. Jose.

Hi Jose, many thanks fo your comments, especially the distance the zoom travels.
There are several new cameras about to come onto the market so I guess I'll keep on looking.

Regards

John

[jourdaj]

I'm seriously thinking of upgrading from the A95 to the A620 but the question of vignetting keeps bothering me.
Is anyone using the A620 with a Zeiss 85 scope, if so what sort of results are you getting with the 20-60 zoom at 20x and 30x?.
On the camera specs it shouldn't be too bad but it depends on the movement of the lens and how close it can be set to the scope eyepiece, does anyone know how similar the movement is compared to the A95?.
Apart from the vignetting problem? this camera would seem to be ideal for digiscoping having virtually all the other requirements needed.

I'd like to hear comments from anyone using this camera, with any scope and any adapter, and perhaps we can come to some conclusion on what is going to be a good lens for digiscoping and what is not, considering their very small differences in focal length, for example the A95 is 38-114mm the A620 35-140mm, 3mm difference at the lower end but what a difference it makes.

I've found through personal use the A95, CP 995 and 4500 all start at 38mm and with a Swarovski AT80HD + 20-60 zoom eyepiece vignetting disappears at about the same camera zoom level, roughly halfway, above this there is no vigneting at any scope magnification camera zoom levels. The Zeiss is a little better, losing vignetting at a slightly lower camera magnification, probably due to having a larger diameter exit pupil.

Looking forward to your comments,

John

John,

Take a look at these threads. I agree that vignetting is a big issue w/ this camera, but I've had great luck w/ it! The A620 is not perfect, and I'm still shopping, but its a nice camera and the plastic adaptor will fit nicely over the 20-60X zoom eyepiece of the Zeiss for handholding the camera to the scope.
Good luck w/ your search!

Jerry

http://www.birdforum.net/showthread.php?t=47808&page=1&pp=25

[erniehatt]

I have the A610, and though I have been having a few problems with the home made bracket I have finally had success and have had no need for an adapter, and have found two positions where vignetting is no problem. Wide angle position the scope eyepiece set at 60X, and full zoom set at 20X. As the A620 is vertualy the same camera it should work. Ernie

[ssemone]

The A620 threaded adapter (LA-DC58F) would it be reasonable to use this with a threaded 1.25" astro eyepiece like one might use on a Pentax spotting scope and avoid any concern of the lens striking the eyepiece? Or would that setup (due to potential for increased distance from eyepiece) lead to vignetting issues?

Would love to hear from folks using the A620 with a fixed eyepiece.

Cheers,

-Sean


I have the A610, and though I have been having a few problems with the home made bracket I have finally had success and have had no need for an adapter, and have found two positions where vignetting is no problem. Wide angle position the scope eyepiece set at 60X, and full zoom set at 20X. As the A620 is vertualy the same camera it should work. Ernie

[hoppeler]

I have just obtained a Kowa TSN-824M and an A620 this week. Initial tests show only one combination that is almost vignetting free and that is with the scope at 60x and the camera at about 1.25x zoom. This camera may work better with eyepieces that have longer eye relief than the Kowa zoom. I will be doing some more comprehensive tests in the next few days.

[Forcreeks]

Hoppeler,
I have Kowa TSN-824 fluorite 1997 model. After beginning digiscoping in 2000, I quickly switched to their 32x fixed eyepiece. It has better exit pupil and better brightness than 20-60 ep. Vignetting was immediately and greatly reduced.
Later I purchased their 21x wide angle ep when it came out couple yrs ago. It's better for ducks at close range, even songbirds when you're close and want a little surroundings to show. Unfortunately, I find it a less sharply focused e.p., but not by much. Of the two, I think 21x has the better spec likely to eliminate the A620 vignetting.

Swaro scopes always vignette more, but appear to me to be the better optics. What an imperfect world, eh? 'Nother example of our trevails: I made and sell a swing-away adapter, the Simplicity Tool DSA-100, but only for straight viewing scopes like yours and mine. It's perfect for my digiscoping needs. Angled scopes sell far more numbers, and work best for numerous reasons in birding. But for digiscoping they basically suck. Their owners can't find the right adapter, or the camera they want is external focus so the lens moves into the e.p. It'll be hard to develop a swing-away adapter for the angled, but I sure wish there was a good one, as do the many folks who've asked me when we'll have one! With swing-away you easily change the lens-to-e.p.-glass distance. I have one universal digiscoping e.p., the EagleEye low-power one where my camera needs to be back of it over 1 1/2 inch to minimize vignette!
Back to the A620, it received rave reviews on both steves-digicams.com and dpreview.com, so I'm really hoping that's the one. BTW, the problem we see so many fuzzy sample shots in the digiscoping forums, I believe is from the attempts to zoom the cameras way up to get rid of vignettes. The shots come out far sharper at low zoom. This is why an adapter/scope setup that minimizes vignette at wide angle range is critical. I think I'll see if local Circuit City has the A-620 now, and take my scope in for a try. That's how I tried out the Olympus C-60 I'm using. The store staff is very good about it, and matches best price. Costco in U.S. selling A620 at $299. If I get that done, I'll post how the vignetting was with the 32x fixed e.p.

Still very much interested in and waiting for reviews on both sites I mentioned of the Coolpix P-3, wish they'd hurry and get done with them. By all means please post thumbnails here as you get more pics and explain the zooms used best you can.

[hoppeler]

Attached are the a couple of examples I took today. these are virtually my first ever photos digiscoping so the quality is probably not the best but I was more interested in testing the amount of vignetting at different settings.

As I said in my previous post the least amount of vignetting I could get was with the Kowa at 60x and the A620 at about 1.25x zoom. You can see a minimal amount of vignetting in this photo of the seagull. My Canon IP4000 printer slightly crops all photos that are printed borderless so even this amount of vignetting does not show in the actual print.

While I would like to have a more flexble combination of camera and scope this will do for the moment. I will try borrowing some other cameras to test with the Kowa and will do some more structured tests tomorrow.

[Neil]

This may not be applicable to the Canon but I've found with my Olympus 7070wz and some of my homemade adapters I need to switch on the camera without the adapter. When I then put the adapter on the camera I'm able to get the lenses closer to use more of the camera zoom without vignetting . When the camera goes to sleep it does remember the lens last position so there is no problem when it wakes up. Neil.

[john-henry]

The A620 threaded adapter (LA-DC58F) would it be reasonable to use this with a threaded 1.25" astro eyepiece like one might use on a Pentax spotting scope and avoid any concern of the lens striking the eyepiece? Or would that setup (due to potential for increased distance from eyepiece) lead to vignetting issues?

Would love to hear from folks using the A620 with a fixed eyepiece.

Cheers,

-Sean

Sean, I think using any type of fixed adaptor with the A620 will give serious vignetting. I believe the only way to use this camera is handholding it to the eyepiece or with a swing-out adaptor where the camera can be mounted close to the eyepiece after finding a camera zoom position that does not vignet.
If only they had stayed with the 3x zoom as in the A95 this camera would be one of the tops for digiscoping.

If you are thinking of trying an adaptor I would recommend Lensmateonline ones rather than the LA-DC58F, they are made of metal and come in 52 or 58mm sizes.

regards

john

[john-henry]

Attached are the a couple of examples I took today. these are virtually my first ever photos digiscoping so the quality is probably not the best but I was more interested in testing the amount of vignetting at different settings.

As I said in my previous post the least amount of vignetting I could get was with the Kowa at 60x and the A620 at about 1.25x zoom. You can see a minimal amount of vignetting in this photo of the seagull. My Canon IP4000 printer slightly crops all photos that are printed borderless so even this amount of vignetting does not show in the actual print.

While I would like to have a more flexble combination of camera and scope this will do for the moment. I will try borrowing some other cameras to test with the Kowa and will do some more structured tests tomorrow.

Everyone seems to be having the same problem with the A620, it's not your scope it's the cameras 4x zoom that's causing the vignetting. Although saying that a few have managed to use it successfully, mainly by handholding the camera to the eyepiece.

Have a look at
http://www.birdforum.net/showthread.php?p=560364#post560364
one of your fellow countrymen is going through the same thing and you might give each other some ideas.

regards

john

[Paul Jarvis]

Took these today, it's a case of finding the right distance, camera setting and zoom settings with this camera. I should add these have had no post processing.

[Forcreeks]

These results are starting to show what the camera can do. Thanks.

[john-henry]

Took these today, it's a case of finding the right distance, camera setting and zoom settings with this camera. I should add these have had no post processing.

Hi Paul, some nice pics there.
Are you hand holding and zooming the camera to a different setting for each pic or have you found a range you can use without having to do that?
Could you post a few details please, scope mag. eyepiece etc. I think a lot of use would be very interested in how you manage it.

regards

john

[Paul Jarvis]

Hi John

I have found it best to use the ep set at 20x and then hand hold the camera with it set at different zooms depending on how far the bird is away. I also use the burst setting mainly to help aviod camera shake, so I can at least get a few sharp pics out of most shots taken.

The advantage I found by hand holding is you can set the eye relief manually to get rid of most of the vignetting. Its worth keeping in mind though when the camera is on 4x you are able to get 80x using th ep on 20x, unlike others that have a max zoom of 3x (A95) and therefore only offer 60x as a max magnification.

My scope is the ES 80ED with the SDL lense.