2X GSO Ed Barlow + 2X DOI teleconverter combo (1 Viewer)

Paul Corfield · Feb 24, 2009

Quite excited about this combo which I tried for the first time today. Very overcast this afternoon and had to shoot at ISO1600 for all the posted examples but I can tell that it's going to be really sharp. It captures small birds at 100m easily. I'm using the DOI HQ7 teleconverter mounted inside the T-mount as described in the modifying teleconverters thread. I have the 2" GSO barlow screwed into the 1.25" adapter that comes with the barlow (mainly because the threads are now stripped on my 2" scope adapter from over use).

First three images are at 100m and all at ISO1600 so take that into account with regards to a slight lack of detail. On the originals at 100% I can pick out very fine hairs around the face of the Thrush (2nd image) which is why I think this combo will work well. In the two closer images it handles the detail easily.

Paul.

Paul Corfield · Feb 25, 2009

Dull and overcast again this morning so I'm still at ISO1600 but these two images will start to show how good this set up is. Loads of details in the white feathers on the Magpie. Also shows how well the camera copes with ISO1600. I've not removed any noise at all from any of the images posted in this thread.

Both these are from 35m and are uncropped, just resized to 800 wide.

Paul.

Paul Corfield · Feb 26, 2009

Still no sun today but it's a bit brighter, bright enough to allow me to drop down to ISO800 and hand hold the scope loose on the tripod axis. Photo below is from 30m range, uncropped. ISO800 1/125 sec shutter speed. Pretty good set up I think.

Paul.

Paul Corfield · Feb 26, 2009

Couple more from today. Magpie is from 100m and photo is cropped just a little to show the bird closer up. Plenty of detail in the whites and fine hair visible under the beak.

Photo of my toy robin at 10m to show a comparison between the scope at 600mm and with the GSO/DOI stack. Loads of detail in the big version and it works out at 1980mm before the crop factor or 3168mm after Canon 1.6X crop factor.

Still got the Antares 3X barlow on order but the shop have said the wait may be up to 28 days.

Paul.

Fritzz · Feb 26, 2009

Paul Corfield said:
Photo of my toy robin at 10m to show a comparison between the scope at 600mm and with the GSO/DOI stack. Loads of detail in the big version and it works out at 1980mm before the crop factor or 3168mm after Canon 1.6X crop factor.

Paul.

Very impressive results.:t: What tripod and which head do you use?

Paul Corfield · Feb 26, 2009

Fritzz said:
Very impressive results.:t: What tripod and which head do you use?

It's nothing fancy, just a really basic tripod without a changeable head and it's a bit of a pig to use but it's done me okay. Once I line it up on something and lock the handle the front of the scope drops about 1" so I have to always aim high and gradually lower it into position. It's really quite awful so if I can get good results then anyone with a good tripod should find it pretty simple. I'll get something better later in the year but this old thing has done me okay for a few years now and I'm used to it's short comings.

Paul.

erniehatt · Feb 27, 2009

Paul, isn't this kind of contradicting some of your earlier post, regarding to much Glass. Ernie

Paul Corfield · Feb 27, 2009

Usually when I talk about too much glass it's with eyepiece/camera lens combinations where you can be up to 15 glass elements quite easily.

With teleconverters/barlows, as long as the glass is of the best quality (photographically) in the first instance then you can think about maybe stacking items. Both the GSO barlow and the DOI work extremely well on their own so there is the minimum of loss in quality once they are put together. Of the other 20 or so 7 element 2X teleconverters I've tried they have only been average to good and by that I mean they work ok over about 30m and then they start to resolve detail less and less. The DOI doesn't really have a limit, it resolve detail at any distance as does the 2" GSO which makes them a good combination. The GSO is only adding a couple of extra glass elements to the set up and it's already proven to be an excellent performer, it's what you put with it that needs to be really good.

Paul.

erniehatt · Feb 27, 2009

Ok Paul, get your drift. I recently got a 3X tc off ebay, don't know how it will go, will test it out tomorrow, it looks ok visually, I can still use it for normal photography if it is not suitable. I can now get down to a respectable 3m, not that I am going to find to much use for that distance. Ernie

erniehatt · Feb 28, 2009

erniehatt said:
Ok Paul, get your drift. I recently got a 3X tc off ebay, don't know how it will go, will test it out tomorrow, it looks ok visually, I can still use it for normal photography if it is not suitable. I can now get down to a respectable 3m, not that I am going to find to much use for that distance. Ernie

Tried out the 3X TC today, no birds around, probably gone off for a dirty weekend, but did a couple of static photos to show the results both were at 10m, The Ant is a big crop. What suprised me with the Golf image, the texture to it was not visible to the naked eye, I could not see it without a strong magnifying glass. Ernie

JGobeil · Feb 28, 2009

Nice acquisition Ernie. This TC seems to work well with your TV85. 3X with just one component sure makes life easier when one is looking for reach.

erniehatt · Feb 28, 2009

JGobeil said:
Nice acquisition Ernie. This TC seems to work well with your TV85. 3X with just one component sure makes life easier when one is looking for reach.

Thanks Jules, I dont have a TV85, I have the Williams optics Zenithstar 80 ED APO Scope, I also have a Skywatcher which I got while the other one went out of culmination, That one has to much magnification for my backyard, even the Zenithstar is pushing it's luck. Ernie

Paul Corfield · Feb 28, 2009

Need to see some 100m + shots to see if it's any good which is the sort of range 3x starts to become useful and is a good test to see how the optics resolve detail.

Paul.

erniehatt · Feb 28, 2009

Ok Paul, around my place getting anything like 100m is impossible, I am lucky to see anything further than 40m at a pinch. Any way with temperatures at 34c degrees the heat haze would defeat the object.Ernie

Paul Corfield · Mar 1, 2009

Yeah, at those temperatures you would need to be right next to the bird. :-O

Coming into Spring here now and even with temperatures of 12°c I'm starting to get heat haze issues. It really is the bane of long range scoping.

Paul.

erniehatt · Mar 1, 2009

Yes Paul, it does make things a bit difficult, but we do get the odd day here and there. We are just into Autum now, so give another month and things may be better. I will keep trying. Ernie

erniehatt · Mar 4, 2009

Took a few images with the Gso 2X Barlow, all from 10m, some seem a little on the soft side, but this could be down to shutter speeds the Sparrows were at 1/10s and 1/13s not ideal. The flower looks clearer at 1/80s.

Paul Corfield · Mar 4, 2009

Those shutter speeds seem very slow. Was it very dark or was the ISO too low?

Paul.

erniehatt · Mar 4, 2009

Paul Corfield said:
Those shutter speeds seem very slow. Was it very dark or was the ISO too low?

Paul.

Paul, it was early morning and the area was in fairly heavy shade, and overcast, ISO 200 was used, The E410 is very susceptible to noise even at 100 iso so I am a bit reluctant to raise it, later in the day would be much brighter. Ernie

erniehatt · Mar 5, 2009

These images were at approx 40m one using the GSO 2X Barlow the other the 3X TC, they are both way out, my personal feelings is camera shake simply because there are no real sharp areas. I ruled out lens quality because both images are much the same, except the GSO shows a film over it. Anyone shed any light on it. Ernie

2X GSO Ed Barlow + 2X DOI teleconverter combo (1 Viewer)

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