Pentax LX as night camera

Jimfear · 03-05-2010, 06:48 AM

Wow! Pål those are amazing!

As I see it there are a couple of problems with doing night shots with the LX in auto, the biggest being that you need to have the thing you want correctly exposed somewhat in the middle. Also when I tried long auto exposures it had a tendency to sometimes burn the photos totally, this using Velvia with it's famously bad reciprocity behaviour and it still managed to go 2 or more stops above what I had calculated to be correct. Don't know if this is some fault that my LX has or if it's general.

Now there are also times that the LX is unbeatable, dusk and dawn photos when the light is changing rapidly really shows why you want of the film metering during the exposure.

I don't use auto exposure for night shots, I usually use largest aperture and get a reading of the thing I want correctly exposed and go from there to the settings I want. If there's very little light I crank the ISO dial up to 3200, most of the time that gets reading. So you don't need a camera like the LX to do night shots, but it's such a nice camera you might as well convince yourself you can't live without it and get one.

GeneV · 03-05-2010, 07:06 AM

Originally posted by tuco

That's why I use the old analog Pentax meter instead of a digital spotmeter. The digital meters make you do more in your head. The dial on the analog is easy to turn and just count. No mental gyrations.

Yeah, that would be a good experiments to conduct with Acros. Get that baby fixed and lets see

I like the dial of my cheap, little Sekonic for the same reason. The silver dial even looks like the lens of my baby SpeedGraphic (but that is another forum). It is great to hear that a pro like you thinks the same way.

The LX came back today. Now, for some decent night weather and some time!

oliver939 · 03-22-2010, 02:06 PM

fantastic photos indeed.

I've been into astrophotography about 15 years ago (with good old pratika SLR all a manual) and I wish I can find a pentax film SRL so I can use some of my pentax lenses (with some limitations that I'm sure about yet).

I have a 'old' A-50mm 1.7 which will work but I whish I can use my DA 21mm, DA40mm, and why not my signa 10-20.
I think only the 40mm can really give ok results with a full frame.

Can the LX control the aperture of a DA lens?

Ben_Edict · 03-22-2010, 03:28 PM

Originally posted by oliver939

Can the LX control the aperture of a DA lens?

No, it can't.

Ben

**Pål Jensen** · 04-01-2010, 09:47 AM

Here's another one shot with the LX and the A 35/2.8 wide-open on auto....

Portland Pete · 04-01-2010, 12:51 PM

Now that is just fantastic! Keep posting these wonderful shots.

systemA · 04-05-2010, 01:33 AM

If I'm understanding correctly, you can use the LX in automode in night scenes for up to 45 minutes for an accurate exposure?

Ben_Edict · 04-05-2010, 03:06 AM

Originally posted by systemA

If I'm understanding correctly, you can use the LX in automode in night scenes for up to 45 minutes for an accurate exposure?

The max. auto-exposure time depends on the combination of aperture setting, ISO and ofcourse the scene brightness. 45 minutes seem possible to me.

Ben

tuco · 04-05-2010, 09:03 AM

Originally posted by systemA

If I'm understanding correctly, you can use the LX in automode in night scenes for up to 45 minutes for an accurate exposure?

"Accurate exposure" would be film dependent too. Shoot some BW film that the meter says 30 seconds, for example, and you'd be surprised how far off your exposures is.

edumad · 04-08-2010, 05:44 AM

A friend of mine has an LX and he said its the best camera he has ever tried for exposure fidelity. Because of the reading from the film surface it is suppose to be excellent for long exposures.

mine.cola · 04-08-2010, 06:33 AM

I advice to take multiple shots (if it's possible) with 0, +1, +2 on auto.
Because, as Tuco said, It's film dependent. Pan-F or TRI-X p.ex does not the same in reciprocity. You don't know exactly before development which frame will have the more details. Then when you know your film, you know how it reacts and if the reading is right...
Even if it meter the light reflecting from the film nicely, It will be different with different films (colors or the grey and reflectance from surface can be different). I'm I wrong?

Ben_Edict · 04-08-2010, 07:13 AM

Originally posted by mine.cola

I advice to take multiple shots (if it's possible) with 0, +1, +2 on auto.
Because, as Tuco said, It's film dependent. Pan-F or TRI-X p.ex does not the same in reciprocity. You don't know exactly before development which frame will have the more details. Then when you know your film, you know how it reacts and if the reading is right...
Even if it meter the light reflecting from the film nicely, It will be different with different films (colors or the grey and reflectance from surface can be different). I'm I wrong?

You are quite correct. Different films have different reflectivity and thus influence the metering for longer expsoures.

The LX does not meter off the film surface for fast expsoure times down to 1/75s (the sync speed). Only longer times will be metered off the film surface. For the shorter exposure times there is a reflective print on the first shutter curtain, off which the metering is taken. Quite similar to the Olympus OM method, though the Pentax metering pattern looks nicer…

Ben

mine.cola · 04-08-2010, 07:37 AM

Thanks Ben,

I forgot it was only for exposure greater than 1/75th (I was thinking to the LX flash possibilities no more). Indeed, shorter speeds will depend on the path of the shutter curtain and thus to the reflectivity of the shutter curtain.

So if you record a long and peaceful exposure and during that time you flash several times (manually), it will meter off the Film and this will depend on the film reflectivity like for a simple long exposure.

Thanks to you It's clear enough for me.

tuco · 04-08-2010, 08:38 AM

Originally posted by edumad

A friend of mine has an LX and he said its the best camera he has ever tried for exposure fidelity. Because of the reading from the film surface it is suppose to be excellent for long exposures.

So what is the relationship between a film's surface and its reciprocity characteristics that the camera can measure and adjust its time, I wonder.

Would it know, for instance, that this surface is 400TX and a calculated exposure of 100 seconds needs an actual 20 minute exposure?

kunaalbhasin · 04-08-2010, 11:19 AM

The original Olympus OM-2 has a similar specification but reportedly can make autoexposures several times that length.
Interestingly the later "improved" OM-2n has an absolute limit of 2 minutes for autoexposures.

I wonder if the LX exceeds the stated specification in actual use, and if the actual maximum changed over its 20-year production history?

With exposures of this length reciprocity failure becomes a real issue. I'm not certain how one copes.
I wonder if the exposure compensation dial behaves normally at the low extreme of the range?

FWIW I have seen wonderful night photos made with OM-2 and LX cameras.

--

Sounds right.

04-08-2010, 06:33 AM	#41
mine.cola Junior Member Join Date: Jan 2010 Location: Genval Photos: Albums Posts: 35	exposure is film dependent...coatings are different I advice to take multiple shots (if it's possible) with 0, +1, +2 on auto. Because, as Tuco said, It's film dependent. Pan-F or TRI-X p.ex does not the same in reciprocity. You don't know exactly before development which frame will have the more details. Then when you know your film, you know how it reacts and if the reading is right... Even if it meter the light reflecting from the film nicely, It will be different with different films (colors or the grey and reflectance from surface can be different). I'm I wrong?

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03-05-2010, 06:48 AM	#31
Jimfear Veteran Member Join Date: Apr 2007 Location: Uppsala, Sweden Photos: Gallery Posts: 576	Wow! Pål those are amazing! As I see it there are a couple of problems with doing night shots with the LX in auto, the biggest being that you need to have the thing you want correctly exposed somewhat in the middle. Also when I tried long auto exposures it had a tendency to sometimes burn the photos totally, this using Velvia with it's famously bad reciprocity behaviour and it still managed to go 2 or more stops above what I had calculated to be correct. Don't know if this is some fault that my LX has or if it's general. Now there are also times that the LX is unbeatable, dusk and dawn photos when the light is changing rapidly really shows why you want of the film metering during the exposure. I don't use auto exposure for night shots, I usually use largest aperture and get a reading of the thing I want correctly exposed and go from there to the settings I want. If there's very little light I crank the ISO dial up to 3200, most of the time that gets reading. So you don't need a camera like the LX to do night shots, but it's such a nice camera you might as well convince yourself you can't live without it and get one.

03-05-2010, 07:06 AM	#32
GeneV Veteran Member Join Date: Oct 2008 Location: Albuquerque NM Photos: Albums Posts: 9,830	Originally posted by tuco That's why I use the old analog Pentax meter instead of a digital spotmeter. The digital meters make you do more in your head. The dial on the analog is easy to turn and just count. No mental gyrations. Yeah, that would be a good experiments to conduct with Acros. Get that baby fixed and lets see I like the dial of my cheap, little Sekonic for the same reason. The silver dial even looks like the lens of my baby SpeedGraphic (but that is another forum). It is great to hear that a pro like you thinks the same way. The LX came back today. Now, for some decent night weather and some time!

03-22-2010, 02:06 PM	#33
oliver939 Senior Member Join Date: Dec 2009 Location: europe Posts: 156	fantastic photos indeed. I've been into astrophotography about 15 years ago (with good old pratika SLR all a manual) and I wish I can find a pentax film SRL so I can use some of my pentax lenses (with some limitations that I'm sure about yet). I have a 'old' A-50mm 1.7 which will work but I whish I can use my DA 21mm, DA40mm, and why not my signa 10-20. I think only the 40mm can really give ok results with a full frame. Can the LX control the aperture of a DA lens?

03-22-2010, 03:28 PM	#34
Ben_Edict Veteran Member Join Date: Jul 2007 Location: SouthWest "Regio" Photos: Albums Posts: 3,309	Originally posted by oliver939 Can the LX control the aperture of a DA lens? No, it can't. Ben

04-01-2010, 09:47 AM	#35
Pål Jensen Site Supporter Join Date: Dec 2007 Location: Norway Photos: Albums Posts: 4,371	Here's another one shot with the LX and the A 35/2.8 wide-open on auto....

04-01-2010, 12:51 PM	#36
Portland Pete Senior Member Join Date: Dec 2009 Location: Oregon Photos: Albums Posts: 144	Now that is just fantastic! Keep posting these wonderful shots.

04-05-2010, 01:33 AM	#37
systemA Veteran Member Join Date: Nov 2008 Location: New York, NY Posts: 385	If I'm understanding correctly, you can use the LX in automode in night scenes for up to 45 minutes for an accurate exposure?

04-05-2010, 03:06 AM	#38
Ben_Edict Veteran Member Join Date: Jul 2007 Location: SouthWest "Regio" Photos: Albums Posts: 3,309	Originally posted by systemA If I'm understanding correctly, you can use the LX in automode in night scenes for up to 45 minutes for an accurate exposure? The max. auto-exposure time depends on the combination of aperture setting, ISO and ofcourse the scene brightness. 45 minutes seem possible to me. Ben

04-05-2010, 09:03 AM	#39
tuco Pentaxian Join Date: Jul 2009 Location: Pugetopolis Posts: 11,030	Originally posted by systemA If I'm understanding correctly, you can use the LX in automode in night scenes for up to 45 minutes for an accurate exposure? "Accurate exposure" would be film dependent too. Shoot some BW film that the meter says 30 seconds, for example, and you'd be surprised how far off your exposures is.

04-08-2010, 05:44 AM	#40
edumad Senior Member Join Date: Apr 2008 Location: UK Posts: 167	A friend of mine has an LX and he said its the best camera he has ever tried for exposure fidelity. Because of the reading from the film surface it is suppose to be excellent for long exposures.

04-08-2010, 07:13 AM	#42
Ben_Edict Veteran Member Join Date: Jul 2007 Location: SouthWest "Regio" Photos: Albums Posts: 3,309	Originally posted by mine.cola I advice to take multiple shots (if it's possible) with 0, +1, +2 on auto. Because, as Tuco said, It's film dependent. Pan-F or TRI-X p.ex does not the same in reciprocity. You don't know exactly before development which frame will have the more details. Then when you know your film, you know how it reacts and if the reading is right... Even if it meter the light reflecting from the film nicely, It will be different with different films (colors or the grey and reflectance from surface can be different). I'm I wrong? You are quite correct. Different films have different reflectivity and thus influence the metering for longer expsoures. The LX does not meter off the film surface for fast expsoure times down to 1/75s (the sync speed). Only longer times will be metered off the film surface. For the shorter exposure times there is a reflective print on the first shutter curtain, off which the metering is taken. Quite similar to the Olympus OM method, though the Pentax metering pattern looks nicer… Ben

04-08-2010, 07:37 AM	#43
mine.cola Junior Member Join Date: Jan 2010 Location: Genval Photos: Albums Posts: 35	Thanks Ben, I forgot it was only for exposure greater than 1/75th (I was thinking to the LX flash possibilities no more). Indeed, shorter speeds will depend on the path of the shutter curtain and thus to the reflectivity of the shutter curtain. So if you record a long and peaceful exposure and during that time you flash several times (manually), it will meter off the Film and this will depend on the film reflectivity like for a simple long exposure. Thanks to you It's clear enough for me.

04-08-2010, 08:38 AM	#44
tuco Pentaxian Join Date: Jul 2009 Location: Pugetopolis Posts: 11,030	Originally posted by edumad A friend of mine has an LX and he said its the best camera he has ever tried for exposure fidelity. Because of the reading from the film surface it is suppose to be excellent for long exposures. So what is the relationship between a film's surface and its reciprocity characteristics that the camera can measure and adjust its time, I wonder. Would it know, for instance, that this surface is 400TX and a calculated exposure of 100 seconds needs an actual 20 minute exposure?

04-08-2010, 11:19 AM	#45
kunaalbhasin Forum Member Join Date: Jan 2010 Posts: 53	The original Olympus OM-2 has a similar specification but reportedly can make autoexposures several times that length. Interestingly the later "improved" OM-2n has an absolute limit of 2 minutes for autoexposures. I wonder if the LX exceeds the stated specification in actual use, and if the actual maximum changed over its 20-year production history? With exposures of this length reciprocity failure becomes a real issue. I'm not certain how one copes. I wonder if the exposure compensation dial behaves normally at the low extreme of the range? FWIW I have seen wonderful night photos made with OM-2 and LX cameras. -- Sounds right.