Watch out for the video/USB connector

*LeoTaylor* · 09-28-2009, 03:50 PM

Years ago a friend with a Nikon Coolpix warned me about the mini-USB connector on cameras being easily damaged. He said there is a lot of leverage in the cable and very little strain relief in the camera. The same connector is on my K1x0Ds (but not the istD). It is used for both video and USB transfer.

Well, a disaster happened. I was taking astrophotos in my observatory with my filterless K110D. I use both the video cable (for focusing on a 13 in monitor) and the USB cable (download photos to a computer). Other times I take the memory card out and run indoors to download.

It was dark of course, and I stepped on the cable. It fell to the floor. I went to plug it back in and there was nothing inside the camera connector. A little jiggling around and I could see a metal connector flopping around inside. Now I don't dare turn it on until I can take it apart and remove the broken piece. I've had the camera apart once before when I removed the filter. I broke it then, and paid Pentax $212 to fix my 4 day old K110D. Without the connector the camera is almost useless for astro since it is very difficult to focus on stars with the little LCD display. It does make a killer IR camera!

Bottom line: Be very careful of that connector. If you yank on the cable you may twist the internal connector right off the main circuit board.

Fortunately I now have an istD I can use for astro. It won't be able to do nebulas with it's internal filter, but after 2.5 years I was running out of bright nebulas to image. I will secure the cables so they can't be stepped upon!

The istD connector looks a bit sturdier.

opiedog · 09-28-2009, 08:33 PM

leo,

thanks for the warning.
i'm intrigued though how you were able to use an external monitor to do the focusing.
how did you do it?

thanks!

jordan

*LeoTaylor* · 09-29-2009, 07:05 AM

Originally Posted by opiedog

I'm intrigued though how you were able to use an external monitor to do the focusing. jordan

Hi Jorden,

I had a old 13 CRT TV left over after the Digital TV conversion in the Spring. I made a tall stand to place the monitor at a comfortable position by my telescope in my observatory. The K110D video cable went from the camera "mini USB" connector to the yellow RCA jack on the front of the TV. As soon as it is plugged in the LCD display goes blank and everything appears on the CRT monitor.

Remember, everything in astrophotography is manually focused. Even an AF lens must be used manually since the camera can't focus on a single bright star. Mainly I use telescopes or manual lenses anyway. You can't adjust in "real time", rather you check, adjust, check, adjust, repeat.

The problem is the dot is way too small to focus on the small LCD screen or viewfinder. With wide angle lenses you can't even see the stars. You can get close by pressing a lot of buttons: Display, zoom, center, increase zoom, repeat for each of many adjustments. I've done that in the past, and before I found the istD video cable I did that last week. This must repeated until you get the focus perfect. In astro close isn't good enough. The video monitor image is big enough to adjust using the 1 second display after the shot without pressing any camera buttons.

I often use an aid called a Bahtinov Mask. This "filter" is a black disk with an odd pattern of slots. It makes it easy to see how far off focus you are. Unlike any other method I've seen it also indicates the direction to turn the focus! I can make focus adjustments much quicker then just trying to make a round dot as small as possible.

*wildlifephotog* · 09-29-2009, 07:10 AM

So you are using the slideshow feature to use the CRT?

I've not finished my coffee, so I may be missing something. LOL

*LeoTaylor* · 09-29-2009, 06:34 PM

Originally Posted by wildlifephotog

So you are using the slideshow feature to use the CRT?

I don't even know what the slide show feature is!

I just connect the monitor and use it. There are no camera settings needed to use an external monitor.

*LeoTaylor* · 09-29-2009, 06:44 PM

Here is an update to the saga.

I removed the seven screws on the bottom of the camera, knowing to keep track of the three different lengths.

I did not completely remove the bottom, just opened it a little and shook the body. Out fell the connector. You can see from the photo the VIDEO / PC hole is very dark.

The tiny connector has many small pins and seems to be surface mount. That explains why a little tug pulled it off the circuit board. If it had tabs soldered through the board I think it would be stronger. On the opposite end of the board is the door open switch which I ripped off when I removed the IR filter years ago. Again, surface mount.

Camera works and will still get some action as an IR camera. It is over 100 times faster than my K100D. With a Hoya 72 I can take daytime photos at 1/1000 second and less!

opiedog · 09-29-2009, 07:14 PM

Originally Posted by LeoTaylor

Hi Jorden,

I had a old 13 CRT TV left over after the Digital TV conversion in the Spring. I made a tall stand to place the monitor at a comfortable position by my telescope in my observatory. The K110D video cable went from the camera "mini USB" connector to the yellow RCA jack on the front of the TV. As soon as it is plugged in the LCD display goes blank and everything appears on the CRT monitor.

Remember, everything in astrophotography is manually focused. Even an AF lens must be used manually since the camera can't focus on a single bright star. Mainly I use telescopes or manual lenses anyway. You can't adjust in "real time", rather you check, adjust, check, adjust, repeat.

The problem is the dot is way too small to focus on the small LCD screen or viewfinder. With wide angle lenses you can't even see the stars. You can get close by pressing a lot of buttons: Display, zoom, center, increase zoom, repeat for each of many adjustments. I've done that in the past, and before I found the istD video cable I did that last week. This must repeated until you get the focus perfect. In astro close isn't good enough. The video monitor image is big enough to adjust using the 1 second display after the shot without pressing any camera buttons.

I often use an aid called a Bahtinov Mask. This "filter" is a black disk with an odd pattern of slots. It makes it easy to see how far off focus you are. Unlike any other method I've seen it also indicates the direction to turn the focus! I can make focus adjustments much quicker then just trying to make a round dot as small as possible.

leo,

thanks for your reply.

that's a great idea. i have an 8" celestar that's been gathering dust since my daughter was born. can't find the time. but maybe now i can interest her.

i remember creating a "mask" with 2 circles and the closer these 2 circles are, the more it's in focus. i guess that's almost the same as the bahtinov mask. i can't remember what it was called.

thanks again!

regards,
jordan

Aristophanes · 09-29-2009, 08:37 PM

Originally Posted by LeoTaylor

Other times I take the memory card out and run indoors to download.

Moral: Don't run.

Sorry to hear. Happened to me (sort of) on my old Fuji F30. Sigh.

*LeoTaylor* · 10-02-2009, 05:19 PM

Originally Posted by opiedog

... i remember creating a "mask" with 2 circles and the closer these 2 circles are, the more it's in focus. i guess that's almost the same as the bahtinov mask. i can't remember what it was called.

Two or three circles is called a Hartmann Mask. They are so last year (First occasion to say that, it will be my last as well).

The Bahtinov mask is more sensitive to small focuser changes and indicates what direction to adjust.