How to stop down for a sun shoot

imouse · 06-04-2012, 04:37 PM

We have a transit of Venus across the sun that will not happen again before 2117. I have a K-7 and a neutral filter. How do I step down the aperture so as to get good photos of same? thanks to all for any input. I am in So.Cal and want to get this shoot on the 'morrow.

Adam · 06-04-2012, 04:47 PM

To stop down, turn the rear e-dial in P or Av mode (or M mode if you want to go all manual). You will then see what the aperture is set to in the viewfinder (bigger numbers mean stopped down more).

**top-quark** · 06-04-2012, 05:02 PM

I'm assuming that you have a tripod. If you haven't, I wouldn't bother. No, you won't be seeing another transit of Venus in your lifetime but at least you'll be seeing!

Engage interval shooting (assuming it's available on the K-7). Attach your ND filter and switch to manual mode. Project the output of the viewfinder onto a piece of white card to position the camera. Directly using the viewfinder or live view probably isn't a good idea, ND filter or not. Leave ISO at 100. Press the green button to take a metered reading. Adjust aperture using the rear dial and shutter speed using the front one, checking that the exposure indicator on the top LCD stays in the middle. Fire away.

Unless you've got that GPS widget that moves the sensor to accommodate the Earth's rotation, you'll need to adjust your camera's position periodically.

calsan · 06-04-2012, 06:10 PM

ND filters aren't safe for solar viewing!

pixelsaurus · 06-04-2012, 06:28 PM

Originally posted by calsan

ND filters aren't safe for solar viewing!

+1

ND transmit UV and IR quite well. You should be using a proper reflective solar filter.
Orion Safety Film Solar Filters

**VoiceOfReason** · 06-04-2012, 07:42 PM

Or a sheet of #14 welders glass. In my case I couldn't find it, so am using 2 sheets of #10, and I will NOT be using the viewfinder.

imouse · 06-05-2012, 06:46 AM

Thanks to all....

Venturi · 06-05-2012, 07:21 PM

Kind of late into this thread, but developed B&W film (Silver based, not C-41) works quite well. This is the traversal using a piece of Fujifilm Neopan 400 taped to an ND filter:

1/125s, ISO 100, f/11
K20D, Tamron 70~300mm 1:4.5~5.6, Vivitar 2X teleconverter

imouse · 06-06-2012, 06:29 AM

Very good shot. Thank you for sharing. Will look at mine on the 'morrow.
I have similar outfit but w/ a K-7 w/o the Vivitar teleconverter. 300+ shots.

06-04-2012, 04:47 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 43,259	To stop down, turn the rear e-dial in P or Av mode (or M mode if you want to go all manual). You will then see what the aperture is set to in the viewfinder (bigger numbers mean stopped down more). Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com's high server and development costs are user-supported. You can help cover those costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

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06-04-2012, 04:37 PM	#1
imouse New Member Join Date: May 2012 Posts: 20	How to stop down for a sun shoot We have a transit of Venus across the sun that will not happen again before 2117. I have a K-7 and a neutral filter. How do I step down the aperture so as to get good photos of same? thanks to all for any input. I am in So.Cal and want to get this shoot on the 'morrow.

06-04-2012, 05:02 PM	#3
top-quark Site Supporter Join Date: Oct 2011 Location: Aylesbury, Bucks Photos: Albums Posts: 492	I'm assuming that you have a tripod. If you haven't, I wouldn't bother. No, you won't be seeing another transit of Venus in your lifetime but at least you'll be seeing! Engage interval shooting (assuming it's available on the K-7). Attach your ND filter and switch to manual mode. Project the output of the viewfinder onto a piece of white card to position the camera. Directly using the viewfinder or live view probably isn't a good idea, ND filter or not. Leave ISO at 100. Press the green button to take a metered reading. Adjust aperture using the rear dial and shutter speed using the front one, checking that the exposure indicator on the top LCD stays in the middle. Fire away. Unless you've got that GPS widget that moves the sensor to accommodate the Earth's rotation, you'll need to adjust your camera's position periodically.

06-04-2012, 06:10 PM	#4
calsan Pentaxian Join Date: Nov 2008 Location: Perth, Australia Photos: Gallery Posts: 1,387	ND filters aren't safe for solar viewing!

06-04-2012, 06:28 PM	#5
pixelsaurus Veteran Member Join Date: Jul 2007 Location: Levin, NZ Photos: Gallery \| Albums Posts: 795	Originally posted by calsan ND filters aren't safe for solar viewing! +1 ND transmit UV and IR quite well. You should be using a proper reflective solar filter. Orion Safety Film Solar Filters

06-04-2012, 07:42 PM	#6
VoiceOfReason Emperor and Senpai Join Date: Jun 2010 Location: Nashville, IN Posts: 5,419	Or a sheet of #14 welders glass. In my case I couldn't find it, so am using 2 sheets of #10, and I will NOT be using the viewfinder.

06-05-2012, 06:46 AM	#7
imouse New Member Join Date: May 2012 Posts: 20 Original Poster	Thanks to all....

06-05-2012, 07:21 PM	#8
Venturi Veteran Member Join Date: Mar 2008 Location: Tulsa, OK Photos: Gallery Posts: 2,639	Kind of late into this thread, but developed B&W film (Silver based, not C-41) works quite well. This is the traversal using a piece of Fujifilm Neopan 400 taped to an ND filter: 1/125s, ISO 100, f/11 K20D, Tamron 70~300mm 1:4.5~5.6, Vivitar 2X teleconverter

06-06-2012, 06:29 AM	#9
imouse New Member Join Date: May 2012 Posts: 20 Original Poster	Very good shot. Thank you for sharing. Will look at mine on the 'morrow. I have similar outfit but w/ a K-7 w/o the Vivitar teleconverter. 300+ shots.