Micro 4/3 OM-D E-M5 Auto ISO: Shutter speed setting?

BigTam

Regular
Jun 23, 2011
Dortmund, Germany
Ron
Hi all,

I've never used a m43 camera, but I have downloaded the E-M5 manual. I can set Auto-ISO max value and the default value in the menus, but can I dictate at what shutter speed the ISO is raised (which I can with my D7000 and X100)?

Or does the E-M5 (or another Olympus m43 camera) set different speeds depending on the focal length of the lens? Or whether IBIS is on?

Anyone know the algorithm?

BigTam
 

pdh

Legend
Jan 2, 2011
Tam, as no-one actually owns an E-M5 yet, I guess there won't be a definitive answer available for that particular camera.
You could try contacting Olympus support of course.

What I can say is that on my E-P2, I can set a minimum auto-ISO, but that I cannot set a relationship between specific shutter speeds and ISO.
 

winginkris

Veteran
Dec 15, 2011
Hi BigTam, sorry I can't help with this, but reading your post brought to my attention the fact that with the x100 you can dictate which shutter speeds the ISO is raised. I've looked through the menus on my x100 and can't see how this is done. I'd like to know how this is done if you can shed a little knowledge my way.
Thanks, Kris
 

BigTam

Regular
Jun 23, 2011
Dortmund, Germany
Ron
... reading your post brought to my attention the fact that with the x100 you can dictate which shutter speeds the ISO is raised. I've looked through the menus on my x100 and can't see how this is done. I'd like to know how this is done if you can shed a little knowledge my way.
Kris, go to the Set-Up menu, page 3 of 6, at the bottom it has ISO AUTO CONTROL. Click right. Then you have ISO AUTO CONTROL (ON or OFF), MAX. SENSITIVITY (I set mine to 3200) and MIN. SHUTTER SPEED. Here you can set a speed, for example 1/80. If the exposure demands a slower shutter speed, the ISO will be raised until the speed is 1/80 or faster. If the ISO reaches the MAX level, it leaves the shutter speed where it falls.

Hope that's clear,

BigTam
 
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krugorg

All-Pro
Sep 26, 2011
Minnesota USA
Kyle Krug
It looks like the Auto ISO implementation is going to be similar to what it was on the E-P3, which did not allow you to fine tune the shutter speed break points. It does factor in the focal length of the lens, but I do not think it makes any difference to the calculation based on whether IBIS is on or off.

I usually now manually set the ISO if I am in a situation where I want to force it to lower shutter speeds.

Hope other Oly owners will jump in the thread and correct if I missed something in the settings!
 

winginkris

Veteran
Dec 15, 2011
Kris, go to the Set-Up menu, page 3 of 6, at the bottom it has ISO AUTO CONTROL. Click right. Then you have ISO AUTO CONTROL (ON or OFF), MAX. SENSITIVITY (I set mine to 3200) and MIN. SHUTTER SPEED. Here you can set a speed, for example 1/80. If the exposure demands a slower shutter speed, the ISO will be raised until the speed is 1/80 or faster. If the ISO reaches the MAX level, it leaves the shutter speed where it falls.

Hope that's clear,
Thanks Tam,
I misunderstood your original post. I thought you were talking about manually choosing a shutter speed, and the camera would choose an ISO setting based on whatever shutter speed was chosen. Thanks for your reply!
Kris

BigTam

BigTam[/QUOTE]
 

pdh

Legend
Jan 2, 2011
I'm quite interested to understand how ISO and focal length can be related ... on the face of it is seems to make no sense at all to me, but maybe I'm just being dim ... can someone explain?
 

krugorg

All-Pro
Sep 26, 2011
Minnesota USA
Kyle Krug
I'm quite interested to understand how ISO and focal length can be related ... on the face of it is seems to make no sense at all to me, but maybe I'm just being dim ... can someone explain?
What I should have said is that, I believe, the camera is aware of what focal length is mounted and incorporates that into the Auto ISO calculation. For example, it goes to a higher ISO to increase the shutter speed if you switch from a 20/1.7 lens to the 45/1.8.
 

BigTam

Regular
Jun 23, 2011
Dortmund, Germany
Ron
I'm quite interested to understand how ISO and focal length can be related ... on the face of it is seems to make no sense at all to me, but maybe I'm just being dim ... can someone explain?
It's about avoiding too low shutter speeds automatically. If the camera (or your setting for the D7000) decides the shutter speed is too low and will cause blurring, it uses Auto-ISO to up the ISO and increase the shutter speed. What constitutes 'too low' is dependant on focal length. A 200mm lens needs a faster shutter speed to avoid blur than a wide-angle
 

Chris2500dk

Top Veteran
Dec 22, 2011
Copenhagen, Denmark
That does make sense, but things like IBIS can really mess up the equation.

One thing I really enjoy on my D5100 is to use auto ISO with M mode. Then I control the shutter speed and aperture and the camera picks an ISO to get a good exposure. I can't use exposure compensation that way, but I guess you can't have everything.
Not sure if the Olympus allows something similar.
 

pdh

Legend
Jan 2, 2011
It's about avoiding too low shutter speeds automatically. If the camera (or your setting for the D7000) decides the shutter speed is too low and will cause blurring, it uses Auto-ISO to up the ISO and increase the shutter speed. What constitutes 'too low' is dependant on focal length. A 200mm lens needs a faster shutter speed to avoid blur than a wide-angle
I see. I did vaguely wonder if that was why.
Not something I feel the need for.
 

madmaxmedia

Veteran
Nov 10, 2010
Los Angeles
The Olympus M 4/3 cameras in general have always been very good about Auto ISO, both in terms of default settings (basing shutter speed/ISO on focal length of lens), and customization (you can choose a faster minimum shutter speed.) It's not going to allow you to create a 2x2 table of shutter speed/ ISO combinations or anything, but that shouldn't be necessary. Pick the minimum shutter speed you would like in the settings, and the camera will do its best (up to maximum ISO) to not go slower than that.
 

pictor

All-Pro
Jul 14, 2010
It's about avoiding too low shutter speeds automatically. If the camera (or your setting for the D7000) decides the shutter speed is too low and will cause blurring, it uses Auto-ISO to up the ISO and increase the shutter speed. What constitutes 'too low' is dependant on focal length. A 200mm lens needs a faster shutter speed to avoid blur than a wide-angle
There is a much better method to achieve what you want. All Olympus can be set to enable Auto-ISO in M mode. So just set the shutter speed to the minimal shutter speed you need to prevent blurring and close the aperture as much as it is necessary to get the depth of field you need. If Auto-ISO is enabled, you will get the lowest possible ISO.
 

amanessinger

New Member
Mar 21, 2012
It's "Slow Limit" in the Custom Flash settings (Cogs-F).

See this thread at dpreview. I tried it with my E-P2 and it works, although unfortunately the formula is not

min{1/35eq_focal_length,slow_limit_value}


but instead

max{1/35eq_focal_length,slow_limit_value}


Thus you can raise the minimum required speed above the inverse of the focal length (35mm equivalent), but you can't lower it. If I set "Slow Limit" to it's minimum value (1/30s), I still get a crossover speed of 1/100s for the 45/1.8, and that regardless of IBIS. If I set "Slow Limit" to 1/160s, it uses 1/160s as crossover speed.
 

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