Search found 12 matches
- Fri May 12, 2017 3:24 pm
- Forum: Equipment Discussions
- Topic: Astrophotographer contemplates extreme macro
- Replies: 31
- Views: 9407
I read your thread early this week and it made no sense to me. Read it again yesterday and it makes sense now :P A couple of days of further research makes a world of difference. Finally understand what the DCR-5320 is! Just a 5 element from objective. From your testing it probably has a focal lengt...
- Thu May 11, 2017 10:40 pm
- Forum: Equipment Discussions
- Topic: Astrophotographer contemplates extreme macro
- Replies: 31
- Views: 9407
I use the Raynox DCR-5320. The focal length of the A+B combination is 170 mm. When you say backfocus do you mean distance from the back of the lens to the sensor? It is 170mm less the distance inside the 5320 to the exit pupil, which I have not measured. 170mm is good, 0.85x whatever micro lens. Ye...
- Thu May 11, 2017 8:51 pm
- Forum: Equipment Discussions
- Topic: Astrophotographer contemplates extreme macro
- Replies: 31
- Views: 9407
The Raynox DCR-5320 is only about $300 so it really isn't expensive by any means. It'll end up working the same way as a telescope does, fixed focal length set at infinity. If you want to focus closer (terrestrial and birding) you move the sensor further back. Alternatively I could leave the focuser...
- Thu May 11, 2017 5:54 pm
- Forum: Equipment Discussions
- Topic: Astrophotographer contemplates extreme macro
- Replies: 31
- Views: 9407
The Raynox 150 looks brilliant, also appears that when reversed that it has a considerable amount of back focus to sensor. Longer back focus helps me as I don't have to worry about getting down to 44mm (Canon) or 46.5mm (Nikon), very difficult with my current planned setup but fine for my D7200. I'm...
- Thu May 11, 2017 3:55 pm
- Forum: Macro and Micro Technique and Technical Discussions
- Topic: Correcting for vignetting
- Replies: 4
- Views: 1124
The technique looks very much like the LCC method in Capture one Pro. I don't know how the LR version works to create a LCC. In Capture one pro( which also "removes" dust) you have to take a reference shot, by placing a white translucent sheet over the lens. Then in Capture one you use that referen...
- Thu May 11, 2017 3:49 am
- Forum: Equipment Discussions
- Topic: Astrophotographer contemplates extreme macro
- Replies: 31
- Views: 9407
You are correct in what your saying Lou, it is something that comes up a lot with DSLR astrophotography when doing emission nebula. Hydrogen is the most abundant element in the universe and its strongest emission is in the red ~656nm. One issue is that about 60% of this emission line is blocked by t...
- Wed May 10, 2017 2:47 pm
- Forum: Macro and Micro Technique and Technical Discussions
- Topic: Correcting for vignetting
- Replies: 4
- Views: 1124
I'm not actually sure if PS has a plugin for it, I don't use PS myself. Flat fielding is a normalised divisional process where the brightest pixel is given a value of 1. Lets say the centre is all very bright ~1 while the extreme corners have 0.5 (half as bright as the centre). The centre won't chan...
- Wed May 10, 2017 5:50 am
- Forum: Macro and Micro Technique and Technical Discussions
- Topic: Correcting for vignetting
- Replies: 4
- Views: 1124
Correcting for vignetting
I notice that there is a lot of discussion about vignetting from some tube lens', some being better than others in that regard. So I thought I would go and lay out some of my astrophotography techniques that may be of interest to others. http://www.photomacrography.net/forum/userpix/6238_For_Macro_1...
- Mon May 08, 2017 8:48 pm
- Forum: Equipment Discussions
- Topic: Astrophotographer contemplates extreme macro
- Replies: 31
- Views: 9407
Shooting RGB individually can also help with correcting for lateral colour shift as the entire channel may need 0.1-2 pixel correction (an issue for planetary imagers). One potential issue is however that unless your lens has very good correction, the RGB channels do not have exactly the same focus....
- Mon May 08, 2017 4:50 pm
- Forum: Equipment Discussions
- Topic: Astrophotographer contemplates extreme macro
- Replies: 31
- Views: 9407
Getting a camera without an anti-aliasing filter will have twice the resolution. Getting a monochrome camera will double the resolution again over that of a Bayer matrix. The benefit of an anti-aliasing filter is that it gives better and truer colour rendition due to the smudging and colour mixing. ...
- Mon May 08, 2017 1:35 am
- Forum: Equipment Discussions
- Topic: Astrophotographer contemplates extreme macro
- Replies: 31
- Views: 9407
Thanks for the thoughts and comments everyone. As it seems to be of biggest interest, I'll start with the electronic focusers. At the moment I have a Precision Digital Focuser (PDF) made by Finger Lakes Instruments (FLI). I have been using this on a 677mm F/5.21 6 element lens which has a corrected ...
- Sun May 07, 2017 4:51 pm
- Forum: Equipment Discussions
- Topic: Astrophotographer contemplates extreme macro
- Replies: 31
- Views: 9407
Astrophotographer contemplates extreme macro
Until recently I've just been dabbling with macro with my Nikon D7200 and what is probably the first iteration of a Tamron 90mm macro F/2.8. Being primarily in astrophotography (I love the technical aspect of both this and macro stacking) I started considering merging equipment from the two fields a...