JGobeil
Nature Photographer
Very interesting comments Paul. Let's see what the others have to say.
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Testing prime focus digiscoping setups (1 Viewer)
- Thread starter JGobeil
- Start date
Very interesting comments Paul. Let's see what the others have to say.
Derry
Well-known member
Jules, your doing a great job and I believe we all agree on the set up,, just another test chart to look at that we were not aware of,, so we shot it and found the good and the bad,,
my only thoughts are you guys with the high price spread (printers) and me trying to work a four year old HP inkjet and normal letter paper,, |
|
the main thing I was questioning was how we are figuring the final mm of our set ups and the more I find to read the cameras X factor should not be a part of our magnification multiplier,, it needs to be listed but not in the mm calculation,, my pennys worth,,
so we are staying with the second chart that test all surface areas of the lens,,
what is our roadmap from this point,, I believe we all have a variety of optics to use but may not be the same set up so final output will vary,, I see Paul has several barlows, I recently sold all my TeleVue barlows as I was not using them in my limited astro activity,,
I'm ready to roll,,
Derry
my only thoughts are you guys with the high price spread (printers) and me trying to work a four year old HP inkjet and normal letter paper,, |
| the main thing I was questioning was how we are figuring the final mm of our set ups and the more I find to read the cameras X factor should not be a part of our magnification multiplier,, it needs to be listed but not in the mm calculation,, my pennys worth,,
so we are staying with the second chart that test all surface areas of the lens,,
what is our roadmap from this point,, I believe we all have a variety of optics to use but may not be the same set up so final output will vary,, I see Paul has several barlows, I recently sold all my TeleVue barlows as I was not using them in my limited astro activity,,
I'm ready to roll,,
Derry
JGobeil
Nature Photographer
Jules, your doing a great job and I believe we all agree on the set up,, just another test chart to look at that we were not aware of,, so we shot it and found the good and the bad,,
my only thoughts are you guys with the high price spread (printers) and me trying to work a four year old HP inkjet and normal letter paper,, |
the main thing I was questioning was how we are figuring the final mm of our set ups and the more I find to read the cameras X factor should not be a part of our magnification multiplier,, it needs to be listed but not in the mm calculation,, my pennys worth,,
so we are staying with the second chart that test all surface areas of the lens,,
what is our roadmap from this point,, I believe we all have a variety of optics to use but may not be the same set up so final output will vary,, I see Paul has several barlows, I recently sold all my TeleVue barlows as I was not using them in my limited astro activity,,
I'm ready to roll,,
Derry
Thanks for the comments Derry.
Your inkjet printer may not be a problem. I have 2 Canon printers: a i9900, 13x19" and a i960 8.5x14". They were purchased 3 or 4 years ago. In order to get good results, I use high res paper that you can easily get at Staples or similar stores. I use Epson High Quality Ink Jet Paper in 8.5x11" format sold in packages of 100 sheets - cheap and very good. I easily resolve the 200 max lp/mm of the Koren chart.
I answered your concern about the camera crop factor in the other thread "Some digiscoping experiments with a DSLR". Just my opinion of course.
IMO, our roadmap is to keep investigating the best way of using chart no. 2 - the one in Protocol V 2.0. I think we need to answer these 3 questions:
1- What to do with the crop factor ?
2- At what distance should we take the picture ?
3- What should be the "effective resolution" formula used to compare setups ?
I strongly suggest we limit our testing to Prime Focus Digiscoping for now. DSLR and scope with magnifying devices in between - barlows, teleconverters and spacers. No eyepieces or camera lenses. Once we are satisfied with the protocol and the results, it will be time to open it to all digiscoping.
Regards
Jules
bluedubius
Rick
One more question before I conduct my test (when weather permits). On the version 2.0 protocol it states that the target should measure 10" x 7.7527" when printed. When I print the V 2.0 target chart and print I get a 10" x 7.5" target when measured between the black borders. Which is it?
Rick
Rick
^^well yeah, for those of us with cameras that have pixels way smaller than 10u ... :-C
This is useful..
http://fourthirds-user.com/2007/10/comparing_the_olympus_e3_to_its_competitors.php
maybe we need to standardize on a camera? The smaller APS-C and 4/3 chips seem to be what everyone's using. I'm thinking that for any reasonable comparison, you have to have at least a APS-C camera... I myself have access to a Canon 40d.
I personally think that both targets should be used. I'm thinking about buying a project board and printing out various targets (like the Koren and ISO) and compiling them as a "super-target." Also, backing it up a bit will definetley put stress on the optic. My basement is almost 90ft long (what like ~30M??) so that could be a control (for me, anyway)- shooting outside at a much farther distance (100M ? that would definatley be pushing it) would be interesting.
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JGobeil
Nature Photographer
Same thing. My error - the exact dimension is 7.527. I will correct in the next version.
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JGobeil
Nature Photographer
I don't think we should do that. The trend is towards full frame sensors. Nikon just introduced the D700 and Canon will be introducing a prosumer full frame DSLR this fall in the 2-3000$ range. We must keep it simple and universal, that way, it will be adequate for everybody including those with P&S cameras.
yes, but how many of us have the larger chips? It seems that that most have the smaller- which obviously outresolve the larger. I've done alot of testing with the Koren chart, and i NEVER hit 200lpmm! i'm pretty depressed, actually, that a Mk III was outdone by a digi rebel (350d)
actually, if you really want full frame, i still have 2 rolls of Kodak TP2415... could shoot that with my F-1 and have it drum scanned...
just to give you an idea of how bad an idea that would be, i attached a picture of my target shot with a AP Starfire 130EDT (much better than pretty much anything mentioned so far- refractor wise) and a EOS 1Ds Mk III.
it's AWFUL.
actually, if you really want full frame, i still have 2 rolls of Kodak TP2415... could shoot that with my F-1 and have it drum scanned...
just to give you an idea of how bad an idea that would be, i attached a picture of my target shot with a AP Starfire 130EDT (much better than pretty much anything mentioned so far- refractor wise) and a EOS 1Ds Mk III.
it's AWFUL.
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Paul Corfield
Well-known member
The photo I posted was with the new 450D if that makes you feel a little bit better.
Paul.
Paul Corfield
Well-known member
Mike, can you post an unresized crop from your photo showing the detail at the 200lpmm end?
Cheers,
Paul.
Cheers,
Paul.
Derry
Well-known member
Mike, one advantage my E3 may have is using live view which I can zoom in to 10X for fine focusing which is very critical,, I'm thinking about a finer focus control for the scope as at 10x on live view a slight amount of presure makes a big difference with such a shallow dof,, it does not even feel like I am turning the knob but I can see the results on the cameras screen,,
have seen photos from that model of canon and you can count the fine hairs on the models head so the camera and your AP scope should have no issues with the 200 line resolution,,
Derry
have seen photos from that model of canon and you can count the fine hairs on the models head so the camera and your AP scope should have no issues with the 200 line resolution,,
Derry
Derry
Well-known member
just posted this on the other thread,,
think we are going to have to draw the line in the sand somewhere and go with what we have,, just reading an article on how much AA filtering Olympus does compared to other brands which has negative impact on resolution,, you just mentioned the Oly E420 which seems to have even more AA as it is rendering some soft photos from the same lens, owners had sharper photos with on prior bodies,,
the more we read the more data to place into the coffer and digest,,
our end result is trying to resolve some fine lines at given distance,, either the equipment can or it cannot,, when we get to the longer distance air turblance is going to have great impact,, how do we control or calculate that into obtaining a sharp image,,
we have the base that Jules prepared with test chart(s),, lets shoot them at prime filling the screen and then start working at given distances to see what we can resolve on the lines at given X mags,,
if we want to use the cameras factor into the calculation I am fine with it,,
Derry
think we are going to have to draw the line in the sand somewhere and go with what we have,, just reading an article on how much AA filtering Olympus does compared to other brands which has negative impact on resolution,, you just mentioned the Oly E420 which seems to have even more AA as it is rendering some soft photos from the same lens, owners had sharper photos with on prior bodies,,
the more we read the more data to place into the coffer and digest,,
our end result is trying to resolve some fine lines at given distance,, either the equipment can or it cannot,, when we get to the longer distance air turblance is going to have great impact,, how do we control or calculate that into obtaining a sharp image,,
we have the base that Jules prepared with test chart(s),, lets shoot them at prime filling the screen and then start working at given distances to see what we can resolve on the lines at given X mags,,
if we want to use the cameras factor into the calculation I am fine with it,,
Derry
Paul Corfield
Well-known member
Air turbulence is dependant on the weather and if it's present then you can see it in the camera viewfinder. The image will shimmer or come in and out of focus and all sorts of other funny stuff. If that's the case then wait for a day when conditions are more favourable.
If the air was like that when trying to photograph a bird then you would have to either get closer to the bird or wait for another day so it's similar with the test chart.
Paul.
If the air was like that when trying to photograph a bird then you would have to either get closer to the bird or wait for another day so it's similar with the test chart.
Paul.
yep- manual focus with live view- all new generation Canon's have it. i always critically focus at 10x.
anyway, i'm pretty convinced that it is camera shake. bogen 3047 head (what i was using) is only rated at ~17lbs. Starfire 130 is ~20.
i'll post up the pics resized later tonight or tommrow. got some important things happening right now- gotta read some Kurt Vonnegut for school tommrow : (
JGobeil
Nature Photographer
Cameras and air turbulence are indeed factors but in my book stability is also a huge factor. A solid and stable tripod/head combinaison, remote or timer triggering and even mirror lock-up in extreme cases, are a must for high magnification precision.
Try tapping with one finger on the scope and watch if there is the vibration in the viewfinder. My Benro C-328 carbon tripod with just 2 legs extended and Manfrotto 501HDV head are rock solid - no vibration at all. Add a remote trigger and I am in business.
When a setup does not bring the expected results, one must find what's wrong and change or fix that component. Unfortunately, it took me almost a year to realize that my Pentax scope was at fault. Now that I have the Astro-Tech refractor, it is a completely different world. Unfortunately, I didn't have time nor wx to fully test it yet but every photograph taken with it has been incredibly sharp.
Don't forget that the weakest link in a chain defines its strength... Don't neglect anything - camera, settings, scope, TC or barlow, tripod, head, wx, technique. That's how we will be able to achieve good results at high magnification. At 60X, the slightest movement or problem is multiplied by 60. Imagine at 100X...
Try tapping with one finger on the scope and watch if there is the vibration in the viewfinder. My Benro C-328 carbon tripod with just 2 legs extended and Manfrotto 501HDV head are rock solid - no vibration at all. Add a remote trigger and I am in business.
When a setup does not bring the expected results, one must find what's wrong and change or fix that component. Unfortunately, it took me almost a year to realize that my Pentax scope was at fault. Now that I have the Astro-Tech refractor, it is a completely different world. Unfortunately, I didn't have time nor wx to fully test it yet but every photograph taken with it has been incredibly sharp.
Don't forget that the weakest link in a chain defines its strength... Don't neglect anything - camera, settings, scope, TC or barlow, tripod, head, wx, technique. That's how we will be able to achieve good results at high magnification. At 60X, the slightest movement or problem is multiplied by 60. Imagine at 100X...
Paul Corfield
Well-known member
Last night I was photographing the moon from my bedroom window and I was in the 3000mm region. One of the tripods legs was up against the bed frame and I was laying on the bed. Just my heartbeat could be detected as a steady vibration through camera viewfinder.
When I'm photographing from indoors, even my cat walking across the carpet a few feet away will be seen as quite a big vibration when looking through the scope. My old tripod that I've had for years is my weakest link and if I can get good results then anyone can. I'll upgrade it later in the year to a nice sturdy Manfrotto.
Paul.
When I'm photographing from indoors, even my cat walking across the carpet a few feet away will be seen as quite a big vibration when looking through the scope. My old tripod that I've had for years is my weakest link and if I can get good results then anyone can. I'll upgrade it later in the year to a nice sturdy Manfrotto.
Paul.
Paul Corfield
Well-known member
Here's the test chart taken with the GSO 2" 2X ED Barlow. Best lens I've used so far. With postage it cost me £33 ($65) brand new from ebay.
3rd image is of the edited RAW file, included this as it shows so much detail.
Make and model of DSLR: Canon 450D
Make and model of scope: Skywatcher Evostar Pro 80ED
Make and model of converter or barlow: GSO 2" 2X ED Barlow
Type, make and model of camera adapter: T-Ring with 2" scope adapter, both unbranded
Length of spacer needed to reach focus: 70mm
Focal length of complete setup in mm: Approx 1920mm after crop factor of 1.6
Measured distance between target and telescope in meters: 15m 59cm
Evaluated resolution number: 20
Speed setting of camera: 1/100sec
ISO: 400
Original picture format (RAW, JPG) and resolution (mpx) RAW 12.2 million pixels
Date and time: 10th july 09:03
Weather conditions (sun and wind): Sunny but target in shade, breezy but garden is sheltered.
Other pertinent information: The barlow lens cell was removed from the barlow body and screwed into the 2" T-mount. The barlow body then becomes the extension tube used to achieve focus. So you get 2 pieces of equipment in one which is handy.
3rd image is of the edited RAW file, included this as it shows so much detail.
Make and model of DSLR: Canon 450D
Make and model of scope: Skywatcher Evostar Pro 80ED
Make and model of converter or barlow: GSO 2" 2X ED Barlow
Type, make and model of camera adapter: T-Ring with 2" scope adapter, both unbranded
Length of spacer needed to reach focus: 70mm
Focal length of complete setup in mm: Approx 1920mm after crop factor of 1.6
Measured distance between target and telescope in meters: 15m 59cm
Evaluated resolution number: 20
Speed setting of camera: 1/100sec
ISO: 400
Original picture format (RAW, JPG) and resolution (mpx) RAW 12.2 million pixels
Date and time: 10th july 09:03
Weather conditions (sun and wind): Sunny but target in shade, breezy but garden is sheltered.
Other pertinent information: The barlow lens cell was removed from the barlow body and screwed into the 2" T-mount. The barlow body then becomes the extension tube used to achieve focus. So you get 2 pieces of equipment in one which is handy.
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Paul Corfield
Well-known member
Took a photo of the Koren chart using the 2" GSO 2X ED barlow. Range was measured to 17m. Resolved all the way to 200.
2nd photo taken with 120mm extension tube between the barlow and the camera. Tested to see if resolving power would suffer. Easily resolved all the way to 200.
Paul.
2nd photo taken with 120mm extension tube between the barlow and the camera. Tested to see if resolving power would suffer. Easily resolved all the way to 200.
Paul.
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bluedubius
Rick
I conducted the test run with the Celestron 80ED and Fuji S2 Pro DSLR today. Looks like similar results to other prime focus tests here.
Make and model of DSLR: Fuji S2 Pro
Make and model of scope: Celestron 80ED 80mm f7.5 (600mm fl)
Type, make and model of camera adapter: built-in to scope
Length of spacer needed to reach focus: appx 60mm
Focal length of complete setup in mm: 900mm
Measured distance between target and telescope in meters: 8 meters
Evaluated resolution number: 20 max
Speed setting of camera: 1/2000 sec
ISO: 200
Original picture format (RAW, JPG) and resolution (mpx) RAW 12mpx
Date and time: 07/11/2008
Weather conditions (sun and wind): sunny no wind
Other pertinent information: extreme humidity (90%)
Rick Phillips
Make and model of DSLR: Fuji S2 Pro
Make and model of scope: Celestron 80ED 80mm f7.5 (600mm fl)
Type, make and model of camera adapter: built-in to scope
Length of spacer needed to reach focus: appx 60mm
Focal length of complete setup in mm: 900mm
Measured distance between target and telescope in meters: 8 meters
Evaluated resolution number: 20 max
Speed setting of camera: 1/2000 sec
ISO: 200
Original picture format (RAW, JPG) and resolution (mpx) RAW 12mpx
Date and time: 07/11/2008
Weather conditions (sun and wind): sunny no wind
Other pertinent information: extreme humidity (90%)
Rick Phillips
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