I have used a Minolta IVF since the time it was introduced, eight or nine years ago. I have not preserved it and it is still doing fine despite it's worn outlook. I am now considering getting a new one to preserve the investment I have made in a booster and spot attachment for this model and also because I love this gear. But I have a problem with a microswitch contact on the adapter attachment which often lead to false measures. This bad contact was not definitly mended in a return to Minolta and I have come to the point where I would never change an attachment in fear of having a misbehaviour. This forced me to adopt a technique based on average reflective light with tone compensation which works pretty fine, still, I would be interested to know if I was the unlucky one or if this problem is known on other and more recent IVFs. By the way, does anyone know of a good not too expensive luxmeter for non-photographic purposes (available light measurments in offices)? Thanks!

-- Paul Schilliger (pschilliger@vtx.ch), November 24, 1999

Answers

Paul,

I can't answer your question on the IVF, because I have an IIIF, but, I can tell you that a company called "The Watt Stopper" in California has an inexpensive illuminance meter. I can't remember if it reads in lux or footcandles, but the conversion is easy (10.76x, most people use 10 for approximation).

These guys make occupancy sensors and the like, but they do have the meter in their line. I think it runs about $100. I consider that inexpensive, considering the Minolta that is pretty much the industry standard is about $800.

One last thing, you can make an approximate illuminance with your Minolta. Note, however, that this is not accurate for human eye sensitivity since it is designed for film, but will make a reasonable approximation.

Set your ASA to 100, and the display to EV, and use the dome diffuser

EV No. Footcandles -2 .076 -1 .15 0 .31 1 .61 2 1.2 3 2.5 4 4.9 5 9.8 6 20. 7 39. 8 78. 9 160. 10 310. 11 630. 12 1300.

and it pretty much doubles for each EV beyond that. You get the idea.

Since EV numbers are logarithmic, there is a bit of error introduced when trying to interpolate between the higher EV numbers, but very little down at the low end.

If you just want to make a few casual readings, I would use this method. If there is a higher purpose, then you can buy a meter designed for reading lux or footcandles.

---Michael

-- Michael Mutmansky (psu4ever@ix.netcom.com), November 24, 1999.

Sorry about that, the mail server did some formatting...

EV No.is equal to Footcandles EV-2 is equal to .076 Footcandles, EV-1 is equal to .15 Footcandles, EV0 is equal to .31 Footcandles, EV1 is equal to .61 Footcandles, EV2 is equal to 1.2 Footcandles, EV3 is equal to 2.5 Footcandles, EV4 is equal to 4.9 Footcandles, EV5 is equal to 9.8 Footcandles, EV6 is equal to 20. Footcandles, EV7 is equal to 39. Footcandles, EV8 is equal to 78. Footcandles, EV9 is equal to 160. Footcandles, EV10 is equal to 310. Footcandles, EV11 is equal to 630. Footcandles, EV12 is equal to 1300. Footcandles,

Hopefully this is a little easier to read.

---Michael

-- Michael Mutmansky (psu4ever@ix.netcom.com), November 24, 1999.

Yes, Paul, I've had exactly the problem you describe with the Minolta IVF. Happened on a shoot, when I realized I didn't believe the readings I was getting. Called Minolta to inquire about where to send it for repair, explained the problem, and the fellow I told me how to fix it myself. Seems that there is a small open slot above the diffuser (dome or flat)that can allow dust and grit to accumulate around a spring-loaded silver pin, which pushes into the body of the meter when a diffuser is mounted. If tiny pieces of grit accumulate around the pin, they can cause it to stick when the diffuser comes off and the spot attachement goes. Removing the batteries and cleaning around the pin solved the problem immediately and to date the problem hasn't recurred. Might try this before giving up on your meter.

-- Steve Singleton (singleton1@bigfoot.com), November 26, 1999.

Steve, Thank you for responding to my question. I now do not feel as lonely as before! I had found on mine that the silver pin activates a switch and this was where the problem came. Just a little dust between the contacts is enough to prevent the switch to operate. Had the head dismanteled and the contacts cleaned, but the functioning remained erratic. Now I would soon detect the two stops error, but when I was new to the system, I had a few ...pretty dark slides! Michael has given some good hints on how to spare an expensive luxmeter by using a conventional light meter with a conversion chart. I'll get to my calculator. Thanks to both of you!

-- Paul Schilliger (pschilliger@vtx.ch), November 27, 1999.