[stevebrot]

The sensitivity range is -6.5 to 20 EV.

The LX metering is something of legend and as with all legends there are elements that are a distortion of fact. The LX meter is silicon photodiode (SPD), the same as most high end cameras of the time. The base sensitivity is comparable to other other cameras with similar meter cells, 1 to EV 19. OTF exposure control in Av mode is stated as -6.5 to 20 EV, with the range on the low end being dictated by the 125s maximum exposure time for the system. Note that the OTF exposure is based upon real-time photon accumulation during exposure, not a static pre-exposure reading.

The camera manual is pretty clear about the distinction in the specifications. In light levels below 1 EV (2s at f/1.4 with ISO 100 film) the meter is not accurate in manual mode. In Av mode for low light, an estimated exposure time is shown in the viewfinder with the final exposure time being based on the OTF system after the shutter opens. Values from the OTF system are never displayed (for obvious reasons) in the viewfinder.


Steve

[ChrisPlatt]

I had a Nikon FM with MD-11 motor drive. Later I upgraded to an FM-2n with MD-12.
The first combination could wake the dead. The second was even louder!

If you need rapid advance the Pentax MX with Winder MX (3+ fps) is considerably quieter.

Chris

[LesDMess]

The LX metering is something of legend and as with all legends there are elements that are a distortion of fact. The LX meter is silicon photodiode (SPD), the same as most high end cameras of the time. The base sensitivity is comparable to other other cameras with similar meter cells, 1 to EV 19. OTF exposure control in Av mode is stated as -6.5 to 20 EV, with the range on the low end being dictated by the 125s maximum exposure time for the system. Note that the OTF exposure is based upon real-time photon accumulation during exposure, not a static pre-exposure reading.

The camera manual is pretty clear about the distinction in the specifications. In light levels below 1 EV (2s at f/1.4 with ISO 100 film) the meter is not accurate in manual mode. In Av mode for low light, an estimated exposure time is shown in the viewfinder with the final exposure time being based on the OTF system after the shutter opens. Values from the OTF system are never displayed (for obvious reasons) in the viewfinder.


Steve

I don't have the schematic to it and although the sensitivity is certainly based on the SPD, I am most certain there are considerably more circuitry associated in providing the final results.
I am sure you incorrectly stated inaccuracy in manual mode as those are easiest to check - as well as reported by magazine reviews, and they are good even on both of my none factory fresh LX's.
In aperture priority auto exposure under controlled lighting, I have tested both of mine to all my assortment of bodies (film and digital) for as long as they can go and again both my bodies are good. The second longest autoexposure body I have is the Olympus OM4T and it goes out to 4 minutes. Besides that I have tested my LX's to over 4 hours and they have never failed to render a proper exposure.

You are right that the LX's metering is legendary but not as a distortion of fact but because it is the only body - past or present of any brand, that can properly aperture priority autoexpose a scene for as long as it takes or the batteries die.

This one is on Kodak Ektar 100 for about 40 minutes . . .



This one on Kodak Gold 100-7 for more than 3 hours . . .




Legendary status can die quickly if there was no truth to it . . .

[LesDMess]

Let's keep in mind that the KX and MX were more inline with Nikon's FT3 and FM releases. Also keep in mind that the MX was a full system machine with motor drives and 250 backs and such. It is also the smallest manual SLR with the largest viewfinder.





With the 80's solid state circuitry reliability being fully tested out in pro bodies (Canon New F1, Pentax LX & Nikon F3) and autofocus coming around, Pentax - as well as most all others, pretty much abandoned manual bodies. Pentax apparently continued the LX through 2000 and Nikon apparently kept the FM2 around followed by the 2001 release of the FM3A. I believe there are others who continued to sell manual focus SLRs like Vivitars and Cosinas that can still be bought new?

[boriscleto]

With the 80's solid state circuitry reliability being fully tested out in pro bodies (Canon New F1, Pentax LX & Nikon F3) and autofocus coming around, Pentax - as well as most all others, pretty much abandoned manual bodies. Pentax apparently continued the LX through 2000 and Nikon apparently kept the FM2 around followed by the 2001 release of the FM3A. I believe there are others who continued to sell manual focus SLRs like Vivitars and Cosinas that can still be bought new?

Nikon still sells the FM10 for about $310.

[LesDMess]

I don't have nor have ever used an FM10 and understand it's not made by Nikon. It's probably like calling the Vivitar k mount bodies a Pentax which I've never used either.

[stevebrot]

I am sure you incorrectly stated inaccuracy in manual mode as those are easiest to check

I got my information from the manual posted at pentax-manuals.com, dated 10/80*. Both the specifications and the meter coupling chart (below, from the Butkus site) indicate a meter range in manual mode of 1 to 19 EV**.



It is expected that meter response above and below the stated range would be non-linear.

The same manual indicates -6.5 to 20 EV for Av mode which corresponds directly to 125s at f/1.2. The 125s figure appears multiple times in the manual, including the section on automated exposure and the shutter spec. The direct quote reads, "The LX will then read the amount of light striking the film plane, select the precise shutter speed required for a proper exposure from continuously variable range from 1/2000th second down to 125 seconds during normal temperatures."

I remembered the long automatic exposures that you have posted multiple times in the past and was a little confused. Perhaps it is a difference in the version of LX or perhaps the long exposure feature was not called out in the manual. In which case, the -6.5 low limit stated for the meter in Av mode might represent the native sensitivity of the OTF meter cell(s) and not the limit for accumulation metering. I suspect that might be the case. The difference in sensitivity range between Av and M modes would be explained by the light loss in passage through the half-silvered main mirror***.

In any case, when comparing the LX to manual exposure cameras like the FM2, the appropriate meter range would be 1 - 19 EV since those are the limits for the camera in manual exposure mode.

* The manual I used may be viewed at http://www.pentax-manuals.com/manuals/mf/pentax_lx_manual_s.pdf (Password = "Pentax")
** EV values are at ISO 100
*** The LX metering system is explained in depth at http://www.mir.com.my/rb/photography/hardwares/classics/pentaxlx/metering/metering.htm



Steve

[stevebrot]

Nikon still sells the FM10 for about $310.

I don't have nor have ever used an FM10 and understand it's not made by Nikon. It's probably like calling the Vivitar k mount bodies a Pentax which I've never used either.

The FM10 is made by Cosina and is essentially the same as the Vivitar V3800N only in Nikon F rather than Pentax K mount. For those requiring a pro-level 35mm SLR, the F6 (made by Nikon) is still available as well.


Steve

[LesDMess]

Steve, The chart is correct and those are the known guaranteed accuracy range of a factory accurate LX meter but of course this does not mean it is inaccurate past it. The legend part is that it does happen to properly expose well beyond it as do both of my used bodies - as well as from other accounts, whether in controlled light setting or real world mixed lighting. The legend just builds up from there since there is no other camera that can do this . . .


Anyway, going back to the original post, the OP will have to decide what features are important to him in a K mount body but 1/4000 and beyond is available.

[zany225]

Thanks guys!! Much more understand!

I think I will consider MX or KX (probably MX because of its size) to be my next film camera.

[j0n4hpk]

I have used both the KX and MX in the past and it boils down to the following: Motor or no motor? If you need a motor drive (Who use something like that with a manual exposure camera? Oh... die-hard film photographers pushing their manual exposure and manual focus skills to the edge on sports, fashion and wedding sessions!), the MX is for you. Now, in my experience, it's easier to use the aperture ring on the lens for exposure control on it (manually prioritize shutter-speed) than the shutter speed on the camera body (for some nefarious reason, the shutter speed dial on my sample was so heavily detented [stops too hard] that I had to use to fingers to turn the shutter-speed dial while holding the camera at eye level instead of using the shutter finger to rotate it). Of course, the KX Motor can be a good contender (just remember that you may need to hunt down it specialized motor drive).
If you don't need a motor drive or winder, the plain KX is a good choice (no hard detents on the shutter-speed dial on the sample I used to use, meaning easy to manually prioritize aperture and using just your shutter firing finger to change shutter speeds while looking through the viewfinder). Either way, both provide a full exposure information on the viewfinder. And last, but not least compatibility with those dozens of millions of K, M, F and FA lenses...

[Canada_Rockies]

The KX accepted motor drive on a special model. I prefer the KX viewfinder info display to the MX. Matching needles is better for me.

[johnha]

The FM2 is a classic NIkon, probably one of the best manual focus SLRs ever made. As much as I like the Pentax K and M series bodies, the only comparable Pentax is likely to be the LX. As a pro body it's simply built better, feels more solid, has bigger dials, better click-stops, smoother film transport and is generally nicer to shoot. It will shoot from 1/75th - 1/2000th without a battery and has the OTF metering and interchangeable finders.

[Cuthbert]

I've a FM (not FM2) and an LX, while I prefer the FM to the MX I consider the LX more capable than the FM, it's a sort of F2 with the dimensions of a FM.

In the K world I've a crazy idea: the K2DMD is the closest thing to an FM2 you can get.

[stevebrot]

The FM2 is a classic NIkon, probably one of the best manual focus SLRs ever made. As much as I like the Pentax K and M series bodies, the only comparable Pentax is likely to be the LX.

I tend to agree. I own a KX, but am highly tempted to get a FM2 one of these days. The difference is immediate on first use.


Steve