using 35 mm camera to meter for 4 X 5

[Michael Onyon]

I am new to large format, having obtained a 4 x 5 camera two months ago. I have read that instead of purchasing a hand-held external meter, the TTL metering of a 35 mm camera can be used instead. That is what I have been trying. I compose and meter with a 35 mm camera set at the equivalent focal length of the 4 X 5 lens I am using (i.e. I set the zoom lens on my 35 mm camera at 62 mm to meter for my 210 mm 4 X 5 lens), then set the 4 X 5 lens to the indicated f/stop and shutter speed. About half the time this works well and the 4 X 5 exposure is perfect (I’m shooting Velvia 100 chromes), but half the time the 4 X 5 exposure is too light or too dark. I am using a Nikon F100 set on matrix metering and I know the meter is accurate because 35 mm exposures come out fine, and its meter matches other 35 mm camera meters. Am I taking the correct approach to metering with a 35 mm camera? Should I buy an external meter? Is it possible to accurately meter to properly expose 4 X 5 film every time, or is bracketing exposure commonly done in large format?
Also, the smallest aperture on my 35 mm camera lens is f/22, but the 4 X 5 lens stops down to f/64. How do I extrapolate beyond f/22? For example, if my 35 mm meter indicates an exposure of 1/10 sec at f/22, what shutter speed should I use on the 4 X 5 camera if I set the f/stop at 1/64?
Thanks,
Mike Onyon

[Sheldon N]

If the meter in your 35mm SLR is accurate, then yes you should be able to use it as your light meter. A couple potential problems...

1) The 35mm's matrix metering makes the wrong decisions for the scene - overexposing a low key scene, underexposing a high key scene, blowing highlights you wanted to save, or clipping shadows that you wanted detail in. This is why spot metering is so popular with LF photographers, so you can control exactly where important parts of the scene fall in the tonal scale.

2) The shutters in your LF lenses may not all be accurate or linear in their exposure times. If the lens/shutter is getting old, a CLA may help. Or you could just have them test your shutter speeds to see if they are reasonably close (within 1/3 stop or so).

3) The aspect ratio between 35mm and 4x5 is different, which could make a difference if you have bright or dark tones at the edges of your 35mm framing. Theses are included in the camera's metering decisions but do not make it into your 4x5 shot.

4) Bracketing helps if you're not sure and it's an important shot. I find it a little expensive so I make sure I get the right exposure (and kick myself if it doesn't turn out).

Yes, you can extrapolate a f/22 reading to higher f stops. The scale is f/22, f/32, f/45, f64, f/90 and so on. Each stop is a doubling or halving of shutter speed. So f/22 at 1/10 is the same as f/64 at 0.8 seconds.

I'd recommend an external spot meter mainly if you want a lighter load to carry around. They all work the same (including the spot meter in your F100). You just need to slow down, meter the individual parts of the scene one at a time, and think through where the highlights, midtones, and shadows are going to fall taking the narrow dynamic range of your film into account. If you do need a dedicated spot meter, I have a spare Pentax Spotmeter V for sale since I just got a Sekonic L-558.

Hope this helps!

[400d]

Isn't this is just a popular topic for new 4x5 users?
I would go for a handheld spotmeter. Although the meter in my 1n is pretty darn accurate, I still have my faith down for the Minolta F, a $180 spotmeter. There are handful of spotmeter out there, Sekonic, Minolta, Pentax, Soligor...etc. These second hand meter can be as low as $50, geez, how much lower do you want?! The fact is these meters are smaller and lighter than a traditional SLR for sure. And for a 1 degree spot metering you need a pretty long lens on a 35mm SLR.
Of coz you can always use DSLR for the preview purpose. For example, the exposure at middle of nowhere in the night will knock your handheld meter out (the light is lower than EV=0), like my spotmeter F, it will give me a good o "E" (Error-too damn dark you idiot!), this is a good time to whip out the 20D, not that 20D can read EV<-1, but you can always do long exposure and estimate the time needed.

[darr]

Mike, You may not be taking any bellows factor into consideration and this could also cause wrong exposures. Without knowing your lenses and bellow lengths, this would be a guess. I would purchase a spotmeter (great for available light) and a tape measure and do a little practice.

[Scott Knowles]

Isn't this is just a popular topic for new 4x5 users?

Yes, it is popular because most new LF users come from 35mm and a fair question, since 35mm cameras have good light meters, and it's a "Why not?". I'm surprised at the positive responses since the last few times people who have asked this question have been verbally pummelled by some folks. Clearly it won't replace a good handheld light meter and has problem with the differences between the two, as stated, bellows factors, filters, format size, etc., but, it will get you in the ballpark, say plus or minus 1 f-stop(?) where you can adjust or bracket. Many 35mm cameras have a wide choice of metering (averaging, spot, weighted, multipoint) to get a reflected exposure.

--Scott--

ps. And yes I have a handheld light meter with my 35mm camera too.

[Ben Crane]

This thread about using a 35 mm or digital camera as a light meter for large format photography seems to come up often. I will have to admit that when I started with 4x5 I used a 35 mm camera for a light meter for about year - mostly as a cost saving issue. It certainly is possible to use a 35 mm camera as a light meter, but after using a pentax digital spotmeter for a while it would be impossible for me to go back. Using a camera for a light meter is simply not ideal for reasons that others have already outlined.

[paulr]

there's nothing wrong with it, if your camera meter works and you know how to use it. it's just a little bulky and cumbersome.

what's ideal is if your camera has a spot meter mode. then you don't have to worry about framing the scene, and trusting your matrix metering to have the same intentions as you (why would it?). but if it's a spot meter, then it's a spot meter.

if it doesn't have that function, you can come close by putting a long lens on the camera and using center weighted metering.

[Vick Vickery]

Never thought about it before, but a 35mm with a center-weighted meter combined with a long lens just about IS a spot-meter! Hmmmmm...I might have to try that, even though I'm still quite happy with my old Weston!

[Chan Tran]

I see no problem using a 35mm camera like the Nikon F100 as a light meter. It's certainly bulkier and slower to use than a spotmeter but it would work almost the same. Depending which lens you have on the camera, but for the most part the spot is small enough. I made the table below
aprox. degree
50mm 4.5
85mm 2.6
105mm 2.1
135mm 1.6
180mm 1.2
200mm 1.1
300mm 0.76

The problem with inaccurate shutter speed and bellow extension as pointed out in earlier posts are there whether you use a hand held spotmeter or using a 35mm camera.
If you make a cardboard dial with 2 dial. One marked in shutter speed and the other in aperture, when you line up the 2 parameters on the dials you can simply read out alternate shutter speed/aperture combinations easily.

[Sheldon N]

If you make a cardboard dial with 2 dial. One marked in shutter speed and the other in aperture, when you line up the 2 parameters on the dials you can simply read out alternate shutter speed/aperture combinations easily.

Thats how the Pentax Spotmeters work. You set the ISO and the EV value, then all possible shutter speed/aperture combinations are lined up on the dial. It's very handy.