C41
Kodak Portra 400
Kodak Portra 400 is a professional C-41 color negative film known for flexible exposure latitude, natural skin tones, and fine grain.
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The LX 250 Quartz is a specialist variant of the Pentax LX introduced around 1990, distinguished by a quartz-crystal oscillator circuit that governs the electronic shutter timing in aperture-priority mode. While the standard LX could hold the shutter open for approximately 125 seconds in AE mode, the 250 Quartz extended that ceiling to 250 seconds with more accurate timing than a conventional RC-circuit approach. The variant retained the full LX feature set: weather-sealed body, interchangeable finders, the off-the-film OTF metering system, and the hybrid shutter with mechanical fallback speeds. It was produced in limited numbers and was never a mainstream catalog item; it appears in some markets as a factory option rather than a separate mass-production model.
Reference
Recommended film stocks for the 35mm format your camera takes.
C41
Kodak Portra 400 is a professional C-41 color negative film known for flexible exposure latitude, natural skin tones, and fine grain.
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Kodak Tri-X 400 is a classic black-and-white film known for strong tonality, visible grain, and documentary character.
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Kodak Gold 200 is a daylight-balanced C-41 color negative film with warm color, moderate grain, and a classic consumer-film look.
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Labs in our directory that process 35mm film.
Before you buy used
The LX 250 Quartz is genuinely rare on the used market; most surface in Japan on Mercari, Yahoo Auctions Japan, or occasionally through specialist dealers in the UK and Germany.
About this camera
The LX taken to its logical extreme - quartz-crystal timing for exposures up to 250 seconds, aimed squarely at astrophotographers.
| Field | Value |
|---|
| Format | 35mm |
| Mount | Pentax K (KA) |
| Years | ~1990 – discontinued |
| Shutter | 250s – 1/2000s electronic; 1/75s, 1/2000s, B mechanical fallback |
| Flash sync | 1/75s |
| Meter | TTL OTF (off-the-film) SPD |
| Modes | Manual, aperture-priority |
| Battery | 2x SR44 (mechanical fallback works without) |
The standard LX was Pentax's professional flagship from 1980. As it aged into the late 1980s and early 1990s, Pentax produced a series of special and limited variants rather than a successor - the LX Titan, the LX 2000, and niche-market versions like this one. The 250 Quartz variant targeted observatory-adjacent use, academic institutions, and scientific photographers who needed timed long exposures beyond what a standard mechanical bulb mode could guarantee with precision. It was not widely advertised and was likely sold through specialist dealers or scientific-supply channels in Japan.
The appeal of the LX 250 Quartz is narrow but coherent: it is one of very few production 35mm SLRs to offer precision-timed automatic exposures beyond two minutes. For astrophotography on film, a 250-second exposure under aperture priority meant the OTF meter (reading off the film plane) could integrate incoming light and theoretically cut the exposure when adequate exposure was reached - though in practice most astrophotographers would use manual bulb timing alongside the quartz clock as a reference or fail-safe.
The OTF metering system of the base LX is the enabling technology here. Because it reads light reflected off the film surface during the exposure, it can respond to changes in scene brightness in real time - a property that matters for fireworks, auroras, or any scene where the light source is intermittent rather than constant.
Full compatibility with the Pentax K-mount ecosystem. The long-exposure use case pairs well with:
BW
Ilford HP5 Plus is a flexible ISO 400 black-and-white film with classic grain and strong push-processing tolerance.
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Kodak Ektar 100 is a fine-grain C-41 color negative film with saturated color and high sharpness.
View profile →Pentax LX 250 Quartz
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