auto-ISO and low light

[MediaFotografie]

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..there's one surprising behavior of the SL at least for me:

 

Assuming we choose auto-ISO with max ISO 3200 and max exposure time 1/f with a f=35mm M-lense like the Summilux-M FLE.

 

Now - christmas time - there is very low light:

• the M (240) goes to ISO 3200 and t = 1/30s; if this doesn't suffice, the M takes longer exposure times
• the SL goes to ISO 3200 and t = 1/30s too - and stops there, so we get underexposed shoots.

Maybe the behavior of the SL is more straightforward, but I hadn't expected this. What do you think?

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[ramarren]

Yes, the SL does not have the "override if the limit has been reached" time extension that the M does. 

 

It's a trade off. With the SL:

• On the one hand, it's less likely that I'll get photos ruined by camera movement.
• On the other hand, it's more likely I'll get unusably underexposed photos if I don't pay attention.

This behavior put me off the first couple of days I was using the SL, but now it just means I have learned to take more care in setting the correct ISO for the extreme lighting situations. 

 

BTW, the other thing to watch out for (with adapted manual lenses) is when you run into metering range limits. I've run into this behavior: with the SL in Manual exposure mode, I set the exposure based on the indicator. If I'm trying for deep DoF in low light, I might set f/8-f/11. The indicator says I have correct exposure, but after making the exposure and reviewing the result, it's underexposed. The problem is that I've hit the metering range limit and the camera has no way to warn me about that fact. This doesn't happen normally with the SL 24-90mm because the camera is in full control of the lens aperture with that lens, and it stays open for metering to extremely low light levels regardless of what your exposure time setting might be. 

 

I've finally figured out that the way to work with small lens openings in very low light using adapted lenses is to exploit exposure simulation mode (tap the FN button twice, you'll see a marker display next to the f/number readout on the first tap and another marker display next to the exposure time on the second tap). Set the view to show the histogram. Once you do that, the display will show the actual illumination after a few moments and the display histogram will accurately reflect exposure properly. Depending on how long an exposure you are working with, you have to wait at least that time to ensure that the exposure simulation has the full exposure period to collect light for metering with. (For example, my little macro test yesterday was being made at 4 second exposure times once I got to f/11 @ ISO 400, so I had to wait at least four seconds for the display to update with the full exposure simulation so I could read the histogram. Changes in the exposure time take a similar amount of time to refresh and reflect correctly as well.)

[Cliff S]

Very clever and thanks for posting this.

 

On the topic of exposure simulation, do we need to do both aperture and shutter or is just one press for aperture enough?

[ramarren]

Very clever and thanks for posting this.

 

On the topic of exposure simulation, do we need to do both aperture and shutter or is just one press for aperture enough?

 

One press on FN gives you aperture simulation (aka DoF Preview) .. It is only really useful with dedicated lenses where the SL has control of the aperture and is designed to show you what the focus zone will cover. With adapted lenses, you stop down the aperture using the controls on the lens to get the same thing. 

 

Two presses gives you the exposure simulation you need for exposure metering, as above.

 

(The side context to be aware of is that the Live Histogram and exposure indicator always tracks the state of the displayed image, not the intended exposure. That was the key to my understanding.)

 

Oh yes: The view simulation mode is re-set to the normal state after making an exposure. You must re-enable it if you need to meter again for changed lighting.

Edited December 21, 2015 by ramarren

[thighslapper]

In low light these days with the 24-90 I tend to use T, switch OIS on and set exposure manually to roughly 3/f for 90mm or 4/f for 50mm and below.

 

This is by far the best tactic in low light ...... and also keeps ISO as low as possible for better final images .....

 

With the M and a fixed lens ...... particularly if w/a...... I have also tended to use a fixed shutter speed (I can handhold  reliably to 2/f) and let ISO vary..... I've not used M lenses much on the SL but I suspect I would do the same.....

Edited December 22, 2015 by thighslapper

[farnz]

Yes, the SL does not have the "override if the limit has been reached" time extension that the M does. 

 

It's a trade off. With the SL:

• On the one hand, it's less likely that I'll get photos ruined by camera movement.
• On the other hand, it's more likely I'll get unusably underexposed photos if I don't pay attention.

This behavior put me off the first couple of days I was using the SL, but now it just means I have learned to take more care in setting the correct ISO for the extreme lighting situations. ...

It seems like, and I treat this the same as, Reciprocity Failure that we used to experience with long exposures on film where the response/performance of the film dropped off the linear part of the graph and one needed to double the exposure time manually to achieve correct exposure.  The difficulty with the SL is that it's difficult to tell when this non-linear behaviour kicks in but it's not an insurmountable problem in my experience because reviewing the picture will indicate under-exposure and subjects shot with long exposures are likely to still be there for another attempt.  With colour transparencies you only found out after the developed film returned from the lab by which time … 

 

Pete.

[ramarren]

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It seems like, and I treat this the same as, Reciprocity Failure that we used to experience with long exposures on film where the response/performance of the film dropped off the linear part of the graph and one needed to double the exposure time manually to achieve correct exposure.  The difficulty with the SL is that it's difficult to tell when this non-linear behaviour kicks in but it's not an insurmountable problem in my experience because reviewing the picture will indicate under-exposure and subjects shot with long exposures are likely to still be there for another attempt.  With colour transparencies you only found out after the developed film returned from the lab by which time … 

 

Even easier, and before you make the exposure, you should be able to just tap the FN button twice to get to exposure simulation and you'll see whether the exposure will be underexposed. The AutoISO maximum exposure time is simply a hard limit on the SL vs a soft limit on the M:

• On the M (in A mode), it tells the camera when to start pushing up the ISO but also allows the max exposure time to grow when the camera has reached your set max limit on the ISO value.
• On the SL, it serves the first function ... it tells the camera when to push up the ISO ... but does not allow the max exposure time limit to be overridden when ISO max is reached. 

Engaging exposure simulation mode should make it clear when you are going to be underexposed. I haven't got the SL with me to give it a test, but it should be pretty easy to determine if you have yours handy. Seeing beforehand that you'll be underexposed is faster and smoother in operation than making one exposure, finding it under, and then having to re-shoot. 

[Lancer365]

Slow shutter speeds can be selected when auto iso is turned off and I so is set to a fixed value manually. Shutter speed can then changed in T mode until you visualise correct exposure. Has been working well for me for night photography. 

[farnz]

Unfortunately T mode is only available with native SL lenses (and I assume T lenses) so the solution regrettably won't help the OP who's using a 35/1.4 Summilux-M FLE.

 

Pete.

[FMB]

I ask myself if it would be posible for SL camera in the next firmware to maintain active always the "light balance for manual exposure setting/exposure compensation value", (even in all kind of programs and exposure settings) like if we were always working in Manual Mode? Then we could be alerted about any kind of under/overexposure in all circumstances,, using autoiso or any automatic setting..

 

Isn't it?

 

Francisco

[ramarren]

I ask myself if it would be posible for SL camera in the next firmware to maintain active always the "light balance for manual exposure setting/exposure compensation value", (even in all kind of programs and exposure settings) like if we were always working in Manual Mode? Then we could be alerted about any kind of under/overexposure in all circumstances,, using autoiso or any automatic setting..

 

Isn't it?

 

Francisco

 

I cant figure out what behavior you want in the above description..

[FMB]

I cant figure out what behavior you want in the above description..

The  main problem I suffered is under exposure for not to have detected I was out  of range.  If every time I was trying to take a photo I can easily see if I'm in Zero or near it then my exposure is OK.

[ramarren]

The  main problem I suffered is under exposure for not to have detected I was out  of range.  If every time I was trying to take a photo I can easily see if I'm in Zero or near it then my exposure is OK.

 

You can see the actual exposure in exposure simulation mode.  Tap FN twice and the screen reflects the actual exposure, including shutter time. An option to lock that mode on might be useful occasionally. 

[FMB]

You can see the actual exposure in exposure simulation mode.  Tap FN twice and the screen reflects the actual exposure, including shutter time. An option to lock that mode on might be useful occasionally. 

I know, but IMO with the system I propose you have an immediate visión not only about if you have a problem but besides you have quantificated  the problem according what the points of deviation in one or other direction say. Also you see panning the camera what happens with your photometer along the scene.

 

But it is only an opinión.

 

Francisco.

 

[Budfox]

I agree with Francisco that the option to see on the meter a measure of the amount of any under or over exposure in T, A and P modes (obviously only when the exposure is out of range in these auto modes) could be useful. At the moment it only serves the purpose of showing any set exposure compensation in all modes other than M.

[mauler]

Firmware 2.0 fixes the metering issue with non-SL/TL lenses.

[mauler]

To an extent, anyway.

[ramarren]

Firmware 2.0 fixes the metering issue with non-SL/TL lenses.

Old thread ... And fw v3.x improved on it a little further.

 

What I would like, since the metering range limit is a hard stop on the metering system, is an indication to say "metering out of range" like some other cameras have had. I seem to recall both my Olympus and Panasonic cameras flash the metering indicators when the range limits ... both high and low ... are hit, regardless of the WYSIWYG presentation in the EVF display. That immediately lets me know that I have to take specific care to adjust exposure beyond the metering readout.

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[profus]

..there's one surprising behavior of the SL at least for me:

 

Assuming we choose auto-ISO with max ISO 3200 and max exposure time 1/f with a f=35mm M-lense like the Summilux-M FLE.

 

Now - christmas time - there is very low light:

• the M (240) goes to ISO 3200 and t = 1/30s; if this doesn't suffice, the M takes longer exposure times
• the SL goes to ISO 3200 and t = 1/30s too - and stops there, so we get underexposed shoots.

Maybe the behavior of the SL is more straightforward, but I hadn't expected this. What do you think?

 

You could try to use auto-ISO in manual mode. Than you would also decide your shutter speed. It works perfect to me

 

Edited April 25, 2018 by profus

[lx1713]

An old thread   but as I just started using auto-ISO to solve a problem, it has a few interesting points. Thanks!

A colleague I hired was using the auto-ISO with his nikons suggested I try it as I was grumbling over the need to long press -ISO and long press flash exposure compensation during an event. He was surprised that when I used my flash, it went to the lowest ISO setting on auto iso. Otherwise he was drooling over the SL.