Minox B lightmeter and ND filter auto adjustment

I have a Query regarding a new 'B' i've just purchased.

The lightmeter seems to work, obviously have to test against a known and run a

film through but note when flicking the ND filter over the lens it doesn't auto

compensate as it should?

The camera seems to be a little used one but may possibly have had the meter

changed from the honeycomb to the lattice type, (i know this would seem odd as

it's exchanging newer to older), However based on the serial and such it's a

possibility and I wondered if this could affect the connector which sets the

auto adjust, (the PC socket type connector inside the meter case and the camera

body).

Any ideas or ways to try and rectify, I ask as i'm intending to use 400 ISO film

for some experimental photography and want the option of shooting landscapes as

well as low light so the ND filter would get some use.

If no immediate or obvious fix or test does anyone know how many stops

difference the ND filter makes?, it should be a set value and if I know it

compensates to one line slower on the meter I can adjust shutter speed

accordingly in that fashion.

 

Cheers,

 

Mike

Changing meters from honeycomb to lattice or viceversa should not affect at all the functions of filter slidebar or reading.Of course if the meter is slightly off(they tend to be more often than not),one has to calculate to see how many stops one has to compensate.To this purpose,meter the subject using a well calibrated meter,one that is working fine.If the meter on your B is stone dead/very low light readings,then have it replaced.Keep in mind that even a working B meter is reading a bit low,due to 40+ yrs since they were built.Also,even a good B meter will be inaccurate in low light conditions,i.e.indoors even well lit.I for one would advise not to open the meter case and start to ruffle in there,could damage the circuts beyond repair.DAG Camera is currently offering services on changing meters and parts,an email should solve the problem.

 

Minox B's ND filters have a filter factour of 10(x10),while other cameras(save the EC),have a filter factour of 2(x2).Since for a value of x2 one has to compensate by allowing one f-stop,it follows that a Minox B grey filter(ND x10)will require 3 1/3 f-strop adjustment of the shutter setting.

 

Hope this all helps,

 

JT

Thanks for the response Julian.

The first part isn't relevant to my query however as the meter as stated works I simply wondered if (due to the possibility of being swapped though I don't think it has) if this could affect the electrical connector which detects when the ND filter is slid over the lens and adjusts the meter reading accordingly, i.e. could one of the pins be not making proper contact and if so how can I get around it?

The meter accuracy is a matter of taking the time to compare to my trusty handheld and running a cassette through and I can deal with any innaccuracies and manual adjustements after.

I don't fully understand your response of the ND having a factor of x10, (although this bit is precisely relevant wand what I wanted to find out), you state that a x2 has a 1 fstop adjustment factor, so from 1/500 to 1/250 = 1 full stop, OK

Then you explain the x10 requires 3 1/3 fstop adjustments which is if i'm not mistaken precisely 1 fstop explained in 1/3 increments which would still = 1/500 to 1/250.

Could you please clarify this or advise if i've misunderstood and thanks for the response.

 

Mike

 

Your text:

Minox B's ND filters have a filter factour of 10(x10),while other cameras(save the EC),have a filter factour of 2(x2).Since for a value of x2 one has to compensate by allowing one f-stop,it follows that a Minox B grey filter(ND x10)will require 3 1/3 f-strop adjustment of the shutter setting.

Sorry ,Mike,misfort typo:the filter factour of other Minox cameras is x4,not x2,so begin your calculations having this figure in mind.The amount of light cut down by the ND filter is the word here:a x2 filter shows twice the normal exposure,which means open up 1 full stop.A x4 filter needs 4 times the normal exposure,and you can get the proper exposure figure by opening 2 full stops from the normal reading.Do keep in mind that each F-stop gives you twice the amount of exposure of the previous reading,when opening up,and they give you 1/2 the amount of the preceding f-stop reading when going the other way,in order to close down).Basically:

 

IF FILTER IS X 2...............ALLOW 1 F-STOP

 

IF FILTER IS X 4...............ALLOW 2 ---,,---

 

IF FILTER IS X 8...............ALLOW 3 ---,,---

 

IF FILTER IS X 10..............ALLOW 3 1/2 F-STOPS

 

Obviously we talk Minox B ND filter here.

 

hope this all makes sense,take care for now

 

regards,

 

JT

JT

That's great and having read this and done a bit more research on it makes much more sense, so if I experiment a bit bracketing around a principal figure of 3 stops difference I should see the 'ideal', it's a niggly little thing which would irk me having to have checked unecessarily as the rest of the camera appears very well kept, stored and clean so a quick manual calc for adjustment when I finally get my film slitter from Mr Doyle and get some FP5 loaded.

 

Thanks for taking the time to explain. Much appreciated.

 

Mike

Forgot to add, the general consensus around the Minoxperts, (I've just created a new word :)

is that the ND is somewhere between 8-10x, I guess this is why the meter is coupled and calibrated due to a poss manufacturing variance, interesting point got others to note with the same issue?

One site somewhere said that the B had a 10x or a 4x which got me worried but most seem to agree it's 8-10. I guess a roll of HP5 and some test pics will answer it for me.

too right,mike...once the slitter is put to good use,shoot a roll as testing material,and see for yourself...you just cannot beat experimenting,in terms of good /bad results.Just a friendly advice:do not do what once I almost did:getting rid of Minox equipment,coz all of this fiddling and guessing kept me nervous.Minox is acting as a very powerful drug:once addicted,hard to get rid of this habit:-))

 

good luck,mate...take care!

 

regards,

Iulian is incorrect. The Minox B's meter automatically adjusts exposure for the ND filter.

You can verify this for yourself. This is also detailed in the instructions for the Minox B

which you can download in the internet.

Bit of a late entry Andrew, thanks for the post but if you re-read my OP you'll note that I state the meter on mine does not automatically compensate as it should when the filter is slid over.