• Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.

    Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

First test with the Olympus OM-D EM-5 (1 Viewer)

JGobeil

Nature Photographer
I received my new toy today and quickly tried it on a scope.

Camera setup:
Lens: Olympus 12-50mm f/3.5-6.3 EZ
Autofocus ON
IBIS ON (I was using a cheap tripod at full height, no remote shutter cable, and it was vibrating)
ISO: 1600
RAW - Sharpened in PS

Digiscoping setup:
Oly OM-D
12-50mm lens
52-43mm step-down ring
Pentax XW-20 Eyepiece
Pentax PF 80-ED Telescope

Photo details:
All photos: Speed: 1/4000 - ISO: 1600 - Uncropped, resized to 800x600, sharpened in PS - distance about 30-35 meters.
1- Lens at 12 mm (480mm FF eq.) - f/3.5 - Minimum reach
2- Lens at 16mm (640mm FF eq.) - f/4.1 - I get a full screen image from then on - Vignetting not corrected
3- Lens at 50 mm (2000 FF mm eq.) - f/6.3 - Maximum reach

General comments:
Please bear in mind that I barely know how to use the camera. These are my first photos.
My regular Benro tripod was not available so I used a cheap Velbon.
The 12-50mm lens has plastic filter threads... less than ideal. I have a 52-52mm ring on order that will stay on the lens permanently.
I'm not satisfied with the results - not sharp enough - I'm quite sure better results can be achieved with an optimised config, good tripod and cable release.
I will also try the Baader Hyperion 21 mm eyepiece
 

Attachments

  • 121211am021kw.jpg
    121211am021kw.jpg
    123.2 KB · Views: 227
  • 121211am025kf.jpg
    121211am025kf.jpg
    127.5 KB · Views: 193
  • 121211am018kw.jpg
    121211am018kw.jpg
    149 KB · Views: 256
Last edited:
Hi Jules,

Just a heads up on calculating the SYSTEM F ratio, e.g. true system F ratio = (scope magnification x true lens focal length) ÷ scope aperture. So in your case with OM-D lens at 50mm telephoto you have (50 x 20) ÷ 80 = F12.5

Shooting F12.5 on m4/3 16mp sensor is probably incurring some diffraction effects. Depending on the subject, how much you crop and your final output you may never be satisfied with the image sharpness.
 
Hi Jules,

Just a heads up on calculating the SYSTEM F ratio, e.g. true system F ratio = (scope magnification x true lens focal length) ÷ scope aperture. So in your case with OM-D lens at 50mm telephoto you have (50 x 20) ÷ 80 = F12.5

Shooting F12.5 on m4/3 16mp sensor is probably incurring some diffraction effects. Depending on the subject, how much you crop and your final output you may never be satisfied with the image sharpness.

Hey, thanks for the info. You may be right, we'll see. I'll make more tests later this week.

I know I can do better, finding a sweet spot for the lens (f/ and focal length), lower ISO, disabling IBIS, using the shutter delay timer and a better tripod, testing the Hyperion eyepiece, etc. How much better ? Don't know. We'll see.

I'm not too concerned because I also have an astro scope I can use in Prime Focus mode, which should yield better results. I can't test it for now because I haven't received the adapter for it.
 
Made more tests today and the results are quite interesting... if not quite surprising !

Don't look at all 4 pictures yet ! Look at the first one - the one with the Xmas decoration. At first glance, it looks pretty good and I think it is quite decent indeed. Much better than the ones taken 2 days ago that were very soft. This time, a better tripod and 12 s. shutter delay.

Now look at the second picture. A CDN 20$ bill taken with the 12-50mm lens set at 25mm - no scope, distance 0.6 m. In order to be perfect, a picture taken with a scope should look like this one, isn't ?

Well, look at the third picture. This one is taken with the scope.
12-50mm lens at 25mm into a 20X XW Pentax eyepiece on a PF-80ED Pentax scope. Distance 9 meters. It is quite sharp, look at the serial number - however, the details are gone.

What's wrong ? Well, to my surprise, it is the eyepiece ! The Pentax XW series eyepieces are renowned to be very sharp but look at the last picture, taken with the Baader Hyperion 21X eyepiece. Now, that's sharp !

Unfortunately, when I finished, it was too dark to photograph the Xmas decoration with the Baader Hyperion eyepiece.

Honestly, I'm quite satisfied with this test. This setup should perform to my satisfaction when birding, which I hope to try during the weekend if the weather permits. I may even decide to purchase a MFT Sigma 30mm f/2.8 EX DN lens. It is cheap, the reports say it is very sharp and it is faster, f/2.8 -vs- f/5.4 for the 12-50mm at 30mm. It is not a zoom lens but it will give me a quite satisfactory 1260mm f.f. eq. - a poor man's 600mm lens with 2X TC on a f.f. Canon...

Would you believe that the Pentax is a 330$ ep. while the Baader Hyperion is only 140$... No comments !

What do you think ? Will I do better in prime focus mode with my Astro-Tech 80ED 560mm 80mm ?
 

Attachments

  • 121214aa013kw.jpg
    121214aa013kw.jpg
    276 KB · Views: 205
  • 121214aa012.jpg
    121214aa012.jpg
    244 KB · Views: 236
  • 121214aa060kw-s2.jpg
    121214aa060kw-s2.jpg
    148.5 KB · Views: 217
  • 121214aa016-2-BH.jpg
    121214aa016-2-BH.jpg
    210.3 KB · Views: 271
Thanks for the info and the link Paul. I find it reassuring to read a confirmation of my findings about the eyepieces.

In my tests, both eyepieces show barrel distortion, the Pentax being MUCH worse.

The first picture, with the lens at 16mm shows how bad the Pentax ep. is for barrel distortion and CA.

The second and third pictures were taken at 20mm for comparison purposes. The second one is with the Pentax ep., the last one with the Baader Hyperion. The Baader is much better - almost no distortion and no CA.

The pictures are originals, no post-processing.

I find it interesting that the Pentax ep. performs beautifully for viewing on the scope. Extremely wide angle of view, very bright and clear. I like it better than the Baader Hyperion.
 

Attachments

  • 121214aa039w.jpg
    121214aa039w.jpg
    114.3 KB · Views: 116
  • 121214aa066w.jpg
    121214aa066w.jpg
    144.2 KB · Views: 120
  • 121214aa014-2w.jpg
    121214aa014-2w.jpg
    147.9 KB · Views: 165
Made more tests today and the results are quite interesting... if not quite surprising !

Don't look at all 4 pictures yet ! Look at the first one - the one with the Xmas decoration. At first glance, it looks pretty good and I think it is quite decent indeed. Much better than the ones taken 2 days ago that were very soft. This time, a better tripod and 12 s. shutter delay.

Now look at the second picture. A CDN 20$ bill taken with the 12-50mm lens set at 25mm - no scope, distance 0.6 m. In order to be perfect, a picture taken with a scope should look like this one, isn't ?

Well, look at the third picture. This one is taken with the scope.
12-50mm lens at 25mm into a 20X XW Pentax eyepiece on a PF-80ED Pentax scope. Distance 9 meters. It is quite sharp, look at the serial number - however, the details are gone.

What's wrong ? Well, to my surprise, it is the eyepiece ! The Pentax XW series eyepieces are renowned to be very sharp but look at the last picture, taken with the Baader Hyperion 21X eyepiece. Now, that's sharp !

Unfortunately, when I finished, it was too dark to photograph the Xmas decoration with the Baader Hyperion eyepiece.

Honestly, I'm quite satisfied with this test. This setup should perform to my satisfaction when birding, which I hope to try during the weekend if the weather permits. I may even decide to purchase a MFT Sigma 30mm f/2.8 EX DN lens. It is cheap, the reports say it is very sharp and it is faster, f/2.8 -vs- f/5.4 for the 12-50mm at 30mm. It is not a zoom lens but it will give me a quite satisfactory 1260mm f.f. eq. - a poor man's 600mm lens with 2X TC on a f.f. Canon...

Would you believe that the Pentax is a 330$ ep. while the Baader Hyperion is only 140$... No comments !

What do you think ? Will I do better in prime focus mode with my Astro-Tech 80ED 560mm 80mm ?

Good test Jules. I was never happy with the Pentax 20 mm eyepiece on the 100 mm scope either and preferred to use Televues. The scope was too big though and I didn't use it much.
Neil.
 
Warning! This thread is more than 11 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.

Users who are viewing this thread

Back
Top