Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Did something stupid:-/

astrophotography dslr
  • Please log in to reply
7 replies to this topic

#1 tclehman1969

tclehman1969

    Messenger

  • *****
  • topic starter
  • Posts: 403
  • Joined: 18 May 2010
  • Loc: SF Bay Area, California

Posted 28 May 2020 - 04:58 PM

First off, nothing broke or was damaged in anyway...just a mental stupid that I completely forgot about!

 

Worked up a platform to attach my DSLR, 50mm finder and 50mm guide scope. Since I deforked my scope a number of years ago, I haven't done any astrophotography using just a camera lens and my camera. That is due to fact that when using my DSLR, an unmodified Canon 77D, I rarely could see through the viewfinder to make certain what I wanted was where I wanted -- partly due to view being a little dark, other part because I'd have to crawl on the ground to see through viewfinder anyway. 

 

So, last night I get a chance to try this out and get everything together to check it out. Even with a guide camera I kept getting massive star trailing on 30 second images! I try without using PHD. Same problem. Restart PHD. Same problem. Move to other parts of the sky. Same problem. No matter what I did I had major star trailing in the images. "What is going on?" I wondered. Checked my connections. All good. Dec and RA bearings locked. I looked through finder and star I centered on is still right in the crosshairs.

 

Then, it hits me. I was using a Tamron 70-200 f2.8 lens....with VIBRATION CONTROL! I left VC turned on and it was trying to correct for the movement it was picking up due to the fork tracking the sky. I turned it off and, gee, surprise, surprise, stars came out perfectly!

 

Stupid.

 

Over the years, this is the first time I have ever used a lens for astrophotography that had vibration control. Used my C8 for imaging, an 80mm telescope for imaging, and on my first DSLRs I hadn't had a lens that had VC on them. Just something I forgot to check.

 

So, I guess the moral of the story is -- Check all your settings!

 

The attached image below is a 30 second image with VC on. I think I changed my ISO and/or f ratio so difference in apparent sky brightness is due to that. These are both just single frames, no stacking or processing in any way.

 

 

Screen Shot 2020-05-28 at 3.01.08 PM.png

 


Edited by tclehman1969, 28 May 2020 - 05:09 PM.

  • markb, Szumi and Noobulosity like this

#2 tclehman1969

tclehman1969

    Messenger

  • *****
  • topic starter
  • Posts: 403
  • Joined: 18 May 2010
  • Loc: SF Bay Area, California

Posted 28 May 2020 - 05:08 PM

This image is another 30 second image with VC off. I recall changing either the ISO and/or f ratio so that is the reason for differences in brightness in images. 

Attached Thumbnails

  • Screen Shot 2020-05-28 at 3.02.17 PM.png

  • Starman27 and markb like this

#3 jimr2

jimr2

    Viking 1

  • -----
  • Posts: 825
  • Joined: 26 Sep 2013
  • Loc: Sparks, NV

Posted 28 May 2020 - 05:23 PM

Don't beat yourself up too much tcl69, I've done the same thing with my vibration-compensated lenses on my Canon DSLR too--several times (in taking timed images of satellites, the ISS, etc., thru a lens on a tripod only...). So it happens to all us! At least I haven't forgotten to take the lens cap off yet!

 

-jim-


  • markb likes this

#4 markb

markb

    Viking 1

  • *****
  • Posts: 826
  • Joined: 16 Jun 2006
  • Loc: Long Island; in transition to Arizona

Posted 28 May 2020 - 05:39 PM

I doubt I would have caught this as fast. I'll slot this under tips to remember.

 

I have the same lens in the non-VC version for Minolta/Sony Alpha.

 

It's a very sharp lens in daylight, but could you comment on it after you have the opportunity to take some more photos?

 

I had planned, 6 months down to road, to try this lens (kind of a Hail Mary attempt, but it's tough to pass up the speed, even stopped down for sharpness) for beginning, light ap.

 

Also on the will-try list is the 100-300 APO-D Minolta and the 500mm f8 Minolta AF cat (perhaps a bit more than a regular cat, having 7 elements) These are two of the sharpest and contrastiest photo lenses I've ever seen, and the cat may equal the sharpness of any telescope I've used, pending side by side comparisions. I have seen an mtf chart that was essentially flat, near the top.

 

The Sony Alpha mount mates to all Minolta AF lenses with full AF in daytime,  making for an inexpensive dual-use (for now) daytime/light AP system.

 

And I did, essentially, 'leave the lens cap on' during the eclipse, at totality I wasted 10 seconds wondering why my roughly on-target pocket camera had a blank display. I knew my photos wouldn't be anything good anyway, so I went back to the 8x40 Minoltas. It turns out I forgot to remove my solar filter used for the partial phases. After a ton of weddings and school events missed by trying to take photos, I knew enough to forget the camera and just enjoy it. No telescope, no camera, just binos was the (proved solid) plan. I have a tracking mount for the camera next time.



#5 tclehman1969

tclehman1969

    Messenger

  • *****
  • topic starter
  • Posts: 403
  • Joined: 18 May 2010
  • Loc: SF Bay Area, California

Posted 28 May 2020 - 06:59 PM

I doubt I would have caught this as fast. I'll slot this under tips to remember.

 

I have the same lens in the non-VC version for Minolta/Sony Alpha.

 

It's a very sharp lens in daylight, but could you comment on it after you have the opportunity to take some more photos?

 

I had planned, 6 months down to road, to try this lens (kind of a Hail Mary attempt, but it's tough to pass up the speed, even stopped down for sharpness) for beginning, light ap.

 

Also on the will-try list is the 100-300 APO-D Minolta and the 500mm f8 Minolta AF cat (perhaps a bit more than a regular cat, having 7 elements) These are two of the sharpest and contrastiest photo lenses I've ever seen, and the cat may equal the sharpness of any telescope I've used, pending side by side comparisions. I have seen an mtf chart that was essentially flat, near the top.

 

The Sony Alpha mount mates to all Minolta AF lenses with full AF in daytime,  making for an inexpensive dual-use (for now) daytime/light AP system.

 

And I did, essentially, 'leave the lens cap on' during the eclipse, at totality I wasted 10 seconds wondering why my roughly on-target pocket camera had a blank display. I knew my photos wouldn't be anything good anyway, so I went back to the 8x40 Minoltas. It turns out I forgot to remove my solar filter used for the partial phases. After a ton of weddings and school events missed by trying to take photos, I knew enough to forget the camera and just enjoy it. No telescope, no camera, just binos was the (proved solid) plan. I have a tracking mount for the camera next time.

Yes, will do a review, if you will, when I get some more time with it pointing skyward. Initial look it looks like it will do well. My sky wasn't too great last night. While it was steady and calm, had an awful lot of sky glow. I'd say naked-eye viewing probably only down to about a 3. M13, couldn't even make out, only could in the 50mm finder. Funny, everyone saying, and I'd have to agree, skies in daytime seem clearer as traffic patterns are greatly reduced, but it still isn't the same when I get up to the mountains way removed from lights! But, this is the SF Bay Area, lots of lights to contend with.


  • markb likes this

#6 tclehman1969

tclehman1969

    Messenger

  • *****
  • topic starter
  • Posts: 403
  • Joined: 18 May 2010
  • Loc: SF Bay Area, California

Posted 28 May 2020 - 07:03 PM

Don't beat yourself up too much tcl69, I've done the same thing with my vibration-compensated lenses on my Canon DSLR too--several times (in taking timed images of satellites, the ISS, etc., thru a lens on a tripod only...). So it happens to all us! At least I haven't forgotten to take the lens cap off yet!

 

-jim-

Well, taking lens cap did happen, too. On my 50mm finder, I found some riflescope lens covers that work perfectly. I don't need to remove, just flip them up. It's fantastic as having lens covers constantly floating around when I am out under the dark. But, haven't done the same with guidescope. I turned on PHD and started looping, couldn't see anything on screen. Played around with the settings and couldn't figure why nothing. It didn't take too long before I realized the cap was still on! 


  • t-ara-fan likes this

#7 jimr2

jimr2

    Viking 1

  • -----
  • Posts: 825
  • Joined: 26 Sep 2013
  • Loc: Sparks, NV

Posted 29 May 2020 - 12:52 AM

Hmmmm, never thought about using flip-up riflescope lens covers on finders--sounds like a great idea! Will have to try to search on-line for some to fit my 50 mm finders too (some are Orions, others Meades and Celestrons….).Anyhow, thanks for the tip tcl!

 

-jim-



#8 Noobulosity

Noobulosity

    Viking 1

  • *****
  • Posts: 743
  • Joined: 10 Jan 2018
  • Loc: Loveland, CO

Posted 31 May 2020 - 04:43 PM

Been there, done that!  I'm glad you got it sorted out for future sessions.  :)




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics





Also tagged with one or more of these keywords: astrophotography, dslr



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics