Let's talk about noise.

[p.giannakis]

The last few days I have been looking for a small photography project to keep me busy. I thought I could download an app (SoundMeter) and measure the noise the shutters made on my cameras. The App has quite good reviews with some of them stating that it is very accurate. I also used my trusty microphone that i use for my work interviews.

I measured the maximum sound made by the cameras - average sound was more difficult to calculate due to ambient noise levels. I measured the noise level at 1 meter and then 0.5 meter. I repeated the test on a kitchen table and on the carpet - there is no noticeable difference.

I was surprised with what i found out.

I can attribute these results in:
a) The App is inaccurate
b) The App is more sensitive to frequencies we humans are not.
c) Measuring the Max levels are not the right way to do it.
d) The above results are accurate.

I was surpriced really - to me the leaf shutter of the rollei sounds less noisy than the F4. No matter how many times I repeated the test - it gave me the same results.

Anyone out there to shed some light to this?

 

[ptpdprinter]

The Rolleicord 1a is 8db louder at 1/300th than at 1/100th? And why would the cameras rank differently at 1m and 0.5m? For example why would the F4 (sllent mode) be 5db louder at 0.5m than at 1m, but the F4(normal mode) be 8db louder at 0.5m than at 1m?

 

[p.giannakis]

The Rolleicord 1a is 8db louder at 1/300th than at 1/100th? And why would the cameras rank differently at 1m and 0.5m?

Yes, good point - i forgot to write that all cameras were tested on 1/500. The Rolleicord goes up to 1/300, that double spring needed for the 1/300 makes it more noisy on that speed than in all other.

Regarding the two different distances, i wanted to get in idea how sound reduces by distance, that is why i did it. But it seems that i got different readings - any sound engeneers that can shed some light?

 

[pixelated]

Those numbers seem awfully high.

 

[markjwyatt]

How did you eliminate mirror slap in the SLRs?

 

[p.giannakis]

How did you eliminate mirror slap in the SLRs?

I didn't. It's part of the measurement.

 

[p.giannakis]

Those numbers seem awfully high.

Maybe, I don't know. Google states that 60dB-70dB is normal conversation sound levels. You would hear an SLR taking pictures while someone is talking thought.

 

[JohnWolf]

Such an interesting topic. Thank you. For comparison, some common noise levels: https://noiseawareness.org/info-center/common-noise-levels/.

I read that the human ear can distinguish 3db differences.

My average picture-taking distance of people is probably 3m and more, so I'd be curious about db fall-off. I've avoided SLRs mainly for this noise factor.

John

Edit: A quick search stated that for every doubling of distance, sound is reduced by 6db. Many of your readings align with that, but also some wide deviations.

 

[JeffS7444]

Anyone out there to shed some light to this?

Spectral analysis of the noise might provide some insight: Some frequencies, particularly lower ones, may be easier to ignore.

 

[p.giannakis]

Spectral analysis of the noise might provide some insight: Some frequencies, particularly lower ones, may be easier to ignore.

Aha, that's what I thought too. The SR-1 makes a high pitch sound while the F5 makes a sort of a clap. To my ear, the SR-1 sounds louder.

 

[the_jim]

This is a wonderful/interesting bit of info. For what it’s worth, my F6 is orders-of-magnitude quieter than my F2 and not much louder than my Zeiss Ikon (all of this is judged by ear…not with a db meter). Also, probably because of its mass and ergonomic design, I’d say the F6 is the camera I’d feel most comfortable with at slow speeds.

 

[OlivierAOP]

Doubling the distance should decrease dB by 6 points due to inverse square law. So that checks out more or less.

 

[p.giannakis]

For example why would the F4 (sllent mode) be 5db louder at 0.5m than at 1m, but the F4(normal mode) be 8db louder at 0.5m than at 1m?

You need to have an F4 (or F5) to understand this. On silent mode the camera triggers and closes the shutter in one cycle and arms the shutter again in another cycle. The second cycle is slower and more quite.

 

[Muggins]

I'd be intrigued to hear what a Nikkormat EL rates - every time I trip mine I wait for the **plop** as the head falls in the basket!

 

[p.giannakis]

I'd be intrigued to hear what a Nikkormat EL rates - every time I trip mine I wait for the **plop** as the head falls in the basket!

If you have a smartphone, download the SoundMeter app and measure it. It should work fine without a microphone too.

 

[shawn]

Were you using any weighting in your measurements? If you were that will be part of the differences. Weighting is just filtering. A weighting will start rolling off response below around 1000hz. C weighting will stay flat longer but will roll off response in the bass.

Shawn

 

[shawn]

Such an interesting topic. Thank you. For comparison, some common noise levels: https://noiseawareness.org/info-center/common-noise-levels/.

I read that the human ear can distinguish 3db differences.

My average picture-taking distance of people is probably 3m and more, so I'd be curious about db fall-off. I've avoided SLRs mainly for this noise factor.

John

Edit: A quick search stated that for every doubling of distance, sound is reduced by 6db. Many of your readings align with that, but also some wide deviations.

A 3db difference in sound is doubling or halving the amount of acoustic power. We can easily distinguish 3dB changes, down to about 1dB is pretty easy and in controlled testing humans can distinguish down to about 0.1dB but we might not perceive it as a volume difference.

Doubling of distance sound is reduced by 6db in free space. In a reflective room the reduction would be lower.

Shawn

 

[p.giannakis]

Were you using any weighting in your measurements? If you were that will be part of the differences. Weighting is just filtering. A weighting will start rolling off response below around 1000hz. C weighting will stay flat longer but will roll off response in the bass.

Shawn

Thanks for your comment Shawn - i dont think i did. I just wrote down the results the app was showing.

 

[shawn]

Thanks for your comment Shawn - i dont think i did. I just wrote down the results the app was showing.

The app very likely applies weighting.

Shawn

 

[JohnWolf]

I tried this with my M6 and M246. On Google Play there are so many apps named "Sound Meter" that I have no idea if it's the same as Pan used.

The M6 varied a lot by how quickly I pressed the shutter button. The Mono measurements was much more consistent.

My very unscientific findings, at 1m and 500 shutter speed:

M6 - 55 db
M246 - 46 db

However, I completely lost confidence in my testing when I clocked my Nikkormat at 57.5 db. The thing sounds like a car door slamming.

John