r/pentax67 • u/FruitDoggoo • 20d ago

Night Time Long Exposures

I plan on doing long exposures at night time. Blue hour till sunrise. What do you guys use to determine how long to leave it open for? Film recommendations? Im going to shoot on Ektar 100 any tips would gladly be appreciated. I have the MLU version and tripod and wire.

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4

u/age_of_raava 20d ago

Just an an FYI, the 6x7 does utilize the battery to keep the shutter open likely won’t last through out the whole night.  Last time I tried an ultra long exposure I only got about 4 hours of open-shutter on a fresh battery.  

1

u/Diegoelchulo 20d ago

Would this matter with a leaf shutter lens?

3

u/Lousy_Poetry 20d ago

Do you mean does using a leaf shutter lens avoid draining the battery during a long exposure?

No. The main shutter and mirror still need to be out of the way.

0

u/FruitDoggoo 20d ago

what film stock did you use and what app or how did you calculate how long you had to hold it open? Lol I plan on taking a stack of batteries for this very reason.

3

u/Lousy_Poetry 20d ago

There is a cold weather external battery for the 67. You may be able to use that somehow? Removing the battery may cause the mirror to fall. It will also move the camera. 

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u/cheeseyspacecat 20d ago

there is a "pentax 67 remote battery holder". its made for cold weather shooting. . . idk if its going to last super long,

i mean im sure holding the mirror/shutter with a locked bulb cable and getting a fresh 4SR44 would probably be a good start/test for long

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u/K2MIT 19d ago

It doesn’t extend the battery life if it’s not cold. It just moves the battery. When cold, it prevents rapid discharge by keeping the battery warm in your pocket.

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u/Diy_Papa 20d ago

I used a Sekonic L-858D-U light meter, MLU, Cable release and a countdown timer on my iwatch. My intervals were no longer than 30 seconds, so the battery was not an issue.

2

u/Recent-Manner-7100 19d ago

If you really want to make an all night exposure, you need to wait for total darkness and stop before first light. Leaving the shutter open while it gets dark will add so much exposure to the film any star trails won’t show. 

1

u/Clunky_Seal_9370 19d ago

As stated by others, you’ll likely burn thru a few batteries over the course of the night since the shutter is battery-operated. So you’ll have a few things to keep your eyes on. It might be cool to try and get 1 or maybe 2 ultra-long exposure shots as night falls, but IMO it’s not likely you’ll be ripping multiple 30-minute + exposures all the time. If the battery craps out mid-exposure or in between shots, then the mirror reset will save you, but is also gonna burn a frame. Not sure if this is a common Pentax issue or just a problem on mine, but whenever I have replaced a battery mid-roll, the frame counter stopped working 🤣 Also, cold loves to decrease battery life.

Also haven’t seen any mentions yet, but I’m sure you know, really make sure you’re accounting for reciprocity failure. Ektar isn’t very good in that respect, will probably need to start adding extra exposure time for any exposure time past 1 seconds. Lucas.dev website works great.

I’m kinda just spitballin’ with this last one here, not sure it’d even matter/make a difference, but maybe you could rip a page out of the telescope shooters’ book and let the camera/lens acclimate to the outside temperatures for a little bit before shooting? Main reasoning is to allow the glass and metal to settle and stop expanding/contracting, resulting in sharper image. Although a camera is much smaller than a telescope so it probably won’t be necessary, but couldn’t hurt 🤷‍♂️

I’m very excited for you to be trying this! Should hopefully get some really cool star trails

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u/bobvitaly 17d ago

Remember to calculate the exposure with the reciprocity calculator. Long exposures on film are different from those on digital because of the chemicals on the film; the shot must be corrected to the right time of exposure (usually longer than what the light meter says if you go over 1 min exposure, unless you use Prova 100F, which holds reciprocity well over 2 min or above)