High ISO 60 Sec Exposure Hack

[robshanghai]

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It's well documented that the M240 is not able to go past 8 seconds shutter duration when set at ISO 800 and further which makes successful Milky Way type of pictures very difficult (standard being something like 30 seconds at ISO 1600 at f2). Well after some searching today I found a post where a guy had discovered that using the M set on auto ISO and in continuous shoot mode when set on bulb he could get 60 seconds. However even when auto ISO high limit was set at 3600 ISO the exposure turned out at 800 ISO the camera not shifting the the highest ISO in the auto setting. Anyway after some experimentation I found that if I took a shot first in A shutter mode at ISO 1600 and then go back to auto ISO it would still use 1600 since auto ISO uses the last used ISO when set to bulb. So with this I was able to get and exposure of 60 seconds at 1600 ISO when ISO is in auto, shutter set to B and in continuous shot C.

Recap

Set auto ISO upper limit to 1600 or above

Set ISO to 1600 and take a picture

Set ISO to auto

Set shutter to B

Set shoot mode to C

Take a shot and hold down the shutter button

After 60 secs it will automatically close the shutter

 

Of course in the real world you would use a cable release and make the necessary exposure time, say 30 seconds for the Milky Way at f2

 

Now I just have to find somewhere to shoot the Milky Way which is not easy when you live in Shanghai :-)

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[jack-tucker]

Thanks for sharing that experience. I will try it myself when I get out of the city, next time.

All the best.

[darylgo]

Great find!!  I was able to duplicate it with my M240 but not in A shutter mode (step 2), that gave me 8 seconds.  In M shutter mode (step 2) I am able to get 60 seconds, and it will continue to take 60 second exposures continuously with a locked cable release.  But alas, it is inconsistent reverting to 8 sec maximum when starting from step one after successful 60 second/iso 1600 exposures.   If I let the camera sit for a few minutes it will again achieve the hack when starting from step one, but not always.   I would be interested to hear about the OP's consistency, perhaps yours is more so.  It is well known that all M's are not equal and the only thing consistent with the M is inconsistency :-)  

 

The M is not optimized for astrophotography but an 8 second exposure at f1.4 iso 3200 will give decent milky way images.    Using a 50mm lens I was able to make a multi image vertical panorama of the milky way that rivaled or exceeded a more optimized sensor and a single shot using a 14mm lens.   

[robshanghai]

Darylgo, step 2 is just for the auto ISO to select ISO 1600 when in M mode, (bulb setting). Auto ISO selects the previous shot ISO when in M mode or so its says when you pull it up in the menu, so yes when you take this shot in A mode you will only get the 8 sec max which is how it should be. I found that once I set the camera up every time I tried it gave me the 60 secs until one time when I turned the thumb wheel which brings up a menu (first time I realised this) that allows you to select the maximum exposure duration when set in B mode. this gives you a number of shutter speed option when set on lower ISO but when set on ISO 1600 you only have 8 secs. Anyway when I moved the thumb wheel and this menu popped up the camera seemed to revert to what it should do and I could only manage an 8 sec max even when going back to step 1 and resetting everything. So I removed the battery (reboot) and started again and all was OK. So yes its seems to be a bit temperamental and easy to go back to what it should actually do and that is take an 8 sec max but taking the battery out for a second or two fixes that. I will try it again and without playing with the thumb wheel or any other settings and see if it can continue consistently at 60 secs. Rob

[robshanghai]

it gets better, I discovered that in ISO settings if I set auto ISO in M mode to on then there is no need to do the first couple of steps to establish a high ISO for M mode. I set ISO ceiling to 3600 in auto ISO and set auto ISO to ON in M mode. I then managed a 60 sec exposure at 3600 ISO. However like Darlgo said its a bit temperamental if you start to play around with settings it stops working and you cant get it to work again without taking the battery out. Need to find a way of making it work more consistently.  But then if you are talking pictures of the Milky Way in the middle of the night its not like you are in a hurry. Rob

[Exodies]

The decisive eon?

[newnew]

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Thank you for all this experimentation. It was said that the max expo was limited to 8 secs to avoid sensor overheating. have you checked if there is any alteration or damage to your sensors after the experiment ?

[darylgo]

Yes, sensor overheating also occurred to me and as set with a cable release locked the camera takes a continuous series of 60 second exposures with a dark frames of 60 seconds in between. So, it can overheat I guess. The camera is made to shoot 60 seconds at low ISO so a higher ISO is simply an electronic change, whether this creates more heat or not I don't know. Also, whenever I shoot astrophotography it is normally cold, 40 degrees F would be a warm night, so it is less likely to heat up under these circumstances but I wouldn't try shooting for hours like my Canon, and home trials are in a toasty 70 degrees.

[darylgo]

Rob, thanks for continuing the effort. I will try the battery removal. Consistency is critical when shooting at night, it is a demanding disorienting situation with minimal flashlight use tolerated if other photographers are nearby.

[robshanghai]

Newnew, I took some shots earlier and sensor looks fine. Of course I am only guessing but I imagine its more about keeping lower noise/banding/hot pixels in the pictures than overheating, Leica would not want comparisons at these extremes with Canon's and Nikon's because they would probably do a better job. So limiting the exposure length means we can't go there. I say this because there no similar limit on live view which must produce the same sensor heat as taking a picture. Possibly someone else is better qualified than me to comment on this. Rob

[darylgo]

The other question that begs asking is whether the 60 sec exposure at ISO 1600 is truly 1600 or a false readout for a lower ISO?

[mjh]

Of course I am only guessing but I imagine its more about keeping lower noise/banding/hot pixels in the pictures than overheating

Noise and hot pixels depend on the temperature – this is the main reason one wants to prevent overheating.

[fotomas]

Does the sensor heat up more on higher ISO at the same exposure time?

[mjh]

No, it doesn’t.

[fotomas]

Would be great if you can go to higher ISO with 60 seconds. Even better would be if you can do more than 60 seconds.

Unfortunately I wasn't able yet to reproduce your findings here. What firmware-version do you have? Mine is 2.0.2.5. M240.

[robshanghai]

firmware 2.0.3.0, one thing i found is that it will not work if you use live view. I took some test shots and for sure it is real high ISO and as expected the shots have quite a large number of hot pixels visible when you zoom in to about 200%, I am not sure how much worse this is than say a Sony A7 but i guess this is the reason Leica limit the exposure time at high ISO