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01-06-2016, 01:15 PM - 3 Likes   #1
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K-5 ISO 80 long exposure

Hi all. With the FF near to come, today I tested my k5 with 25 and 30 seconds long exposures at ISO 80 , just to see noise levels and color reproduction. As expected, I was REALLY pleasured by results. I was on the road to come back home, sunset war far gone, there were just the llast Iights. I shoot RAW+ , image below is jpg from camera , only resized in GIMP to be uploaded here. Obviously the image nees some tweaks in PP (consider it's JPG out of camera) but colours are really near to what my eyes have seen and noise level is so low.
It's a pleasure to rediscover every time that K5 is such a good camera! So my expectation on FF are really huge!
Best regards!
Matteo


Last edited by bm75; 12-24-2016 at 06:32 PM.
01-06-2016, 01:20 PM   #2
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Nice shot.

I don't know of any other Pentax DSLR that goes below ISO 100. Unless the K-1 plumbs exciting new lows in ISO (50 would be great, 25 perfect, anything lower a divine bonus), I will be very sorry to trade up when and if the K-5 finally packs it all in.

SoCaNikon can keep their highs of three million ISO. In a perfect world, I want THREE (and will be happy to top out at a usable 50,000).
01-06-2016, 02:32 PM - 1 Like   #3
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What dictates the base iso? What stops manufacturers from enabling iso 50, 25, or even 1 on their cameras? I mean extended iso is just upping the hardware signal sensitivity, right? What prevents manufacturers from enabling arbitrarily low iso settings through firmware to enable longer exposures or to create digital neutral density filters? Would decreasing the signal sensitivity on sensor have any benefit in dynamic range? The D810's base ISO is 64, it uses the same sensor as the D800 which has a base of 100, the answer seems obvious to me, or am I wrong?

Image looks amazing by the way.
01-06-2016, 02:34 PM   #4
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Thanks pathdoc. I want to keep my k5 until it dies because it performs really well. I miss the film days when I was able to take off the fridge those ISO 64 rolls and use them.
Other brand's offering in APSC segment don't have the same appeal as k5' features. I need a second body but here in Italy it's quite impossible to find k5 IIs to buy so I'm forced to look at k3 or the new FF .

01-06-2016, 02:36 PM - 1 Like   #5
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Beautiful color. Definitely more than one way to shoot landscapes in the dark ☺
01-06-2016, 03:08 PM - 1 Like   #6
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QuoteOriginally posted by Dipsoid Quote
What dictates the base iso? What stops manufacturers from enabling iso 50, 25, or even 1 on their cameras? I mean extended iso is just upping the hardware signal sensitivity, right? What prevents manufacturers from enabling arbitrarily low iso settings through firmware to enable longer exposures or to create digital neutral density filters? Would decreasing the signal sensitivity on sensor have any benefit in dynamic range? The D810's base ISO is 64, it uses the same sensor as the D800 which has a base of 100, the answer seems obvious to me, or am I wrong?

Image looks amazing by the way.

That's because in this day and age manufacturers assume that photographers want cameras that can shoot in near darkness and they have a point. Back in the days of film manufacturers made specialty film that was slow in terms of light sensitivity, but that captured images with minimal grain(ISO 50 and less). Manufacturers had an incentive to produce such films because publishers such as magazines,postcards and books wanted grain-less photos.


With the advent of Digital cameras there was not much grain to worry about. You could get a crystal clear picture from ISO 100 to about 800 or more ! As light sensitivity in sensors increased, a War if you want to call it that was started between camera/sensor manufacturers to see who could produce the highest "usable" sensitivity.


A lot of money was invested in noise reduction software and algorithms, to the point where you can now shoot at ISO 3200 with some cameras and not have to worry about noise.


During the film era photographers who wanted to take pictures in dim light had to carry around a heavy tripod and make use of the Bulb Exposure feature a lot, because high sensitivity films were just not that good. On the other end of the spectrum, you could get crystal clear pictures from slides rated at ISO 50 or below but you often needed a tripod unless you were in the best of light. That all went away with Digital...

Last edited by hjoseph7; 01-06-2016 at 03:39 PM.
01-06-2016, 04:34 PM   #7
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Thanks all.

QuoteOriginally posted by Dipsoid Quote
What dictates the base iso? What stops manufacturers from enabling iso 50, 25, or even 1 on their cameras? I mean extended iso is just upping the hardware signal sensitivity, right? What prevents manufacturers from enabling arbitrarily low iso settings through firmware to enable longer exposures or to create digital neutral density filters? Would decreasing the signal sensitivity on sensor have any benefit in dynamic range? The D810's base ISO is 64, it uses the same sensor as the D800 which has a base of 100, the answer seems obvious to me, or am I wrong?

Image looks amazing by the way.
I think that's right. Unfortunately (or fortunately, for all us pentaxians) in APSC only the K5 offered ISO80 as native base iso. Other brands missed something here.. on FF I don't know... reading some comera feature shows that ISO50 is disposable (but is that real native ISO?) . I'll be pleased to see that feature in more cameras.

@hijoseph7: I agree: Iso 3200-6400 are usable/workable and with fast lenses you can take pictures with the camera handheld (SR helps). But my opinion is that noise is really visible and the main problem with such high ISO is the color accuracy/fine contrast degradation. Noise isn't necessarily a bad thing (fast films had big grain) but in digital (film like) the higher the ISO the worse the color and the contrast of the image (obviously, above certain ISOs). So for static subjects I think the old way (tripod+lowest ISO) is the way to go. what I feel is that K5 is a capable and consistent camera, that allows me to go down to iso80 and up higher than 6400 with acceptable risults within that limit. THAT'S GREAT !!!!!!!! I admit I shoot ISO12800 sometimes but...how big noise there's in those pictures (affecting detalis of the images)!

Best regards. Matteo
01-06-2016, 05:05 PM - 1 Like   #8
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Six minutes at F8 on a K-3 two nights ago as part of the Single in January challenge....


Shot in RAW at ISO 100, no noise reduction required in post processing, just a little care to mask the sharpening to the bits that needed it.


By the way the jump between ISO 80 and ISO 100 in speed is not that large!




01-30-2016, 06:38 PM - 1 Like   #9
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QuoteOriginally posted by bm75 Quote
It's a pleasure to rediscover every time that K5 is such a good camera!

Thanks, Matteo. This inspires me to use my K5 at ISO 80, which I have not done yet. Thanks for sharing such a great photo. Great colors. I agree that the K5 is a great camera. I sometimes think about when to upgrade it, but so far it has given me all that I wanted, along with some very pleasant surprises in addition.




QuoteOriginally posted by southlander Quote
Six minutes at F8 on a K-3 two nights ago as part of the Single in January challenge....

Six minutes - wow! - and that is a very cool shot. Just curious - how did you determine that six minutes was the right amount - is there a formula or something? Having the shutter open for six minutes must have seemed like an eternity.
01-31-2016, 02:28 AM   #10
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Thanks GlennG.
I like k5 a lot and the more I use the more I like. It's so good. Unfortunately, as second body I cannot find an affordable k5 IIs to buy near my country (there are really few cameras and prices are high as a new k3) . I have much expectations on the new FF.
Here another snapshot taken at Iso80 . Edited today just for resizing at 1200*800 (loose much sharpness in this operation). This was from a morning walking I did time ago some hours after a storm near the sea - I had no filters so hightlights were near clipped ( I tried to save exposing for them). I like the texture of the clouds and the sweet "caramel" haze of the sky.
Best regards. Matteo

Last edited by bm75; 12-24-2016 at 06:32 PM.
01-31-2016, 04:25 AM   #11
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QuoteOriginally posted by GlennG Quote

Six minutes - wow! - and that is a very cool shot. Just curious - how did you determine that six minutes was the right amount - is there a formula or something? Having the shutter open for six minutes must have seemed like an eternity.
I knew I had gone outside the 30 seconds max exposure for aperture priority shooting mode and had to go to bulb. Had tried a prior shot around 3 minutes but just darker than I wanted. I've got a reasonable gut feel these days looking at the histogram whilst reviewing images how far underexposed a image is. I took a guess at needing an extra stop or so. Started the posted image thinking about 5 minutes, then added another minute as I went along as I noticed the remaining light was fading away even as I was exposing this shot.

Once you get to long exposures like this, jumping from 3 minutes to six is only one stop additional exposure!

I could have potentially opened up the aperture to cut the exposure time but I knew from earlier images taken while in reasonable light that f8 or thereabouts gave the DOF I needed. By the time I started the posted image I couldn't see anything useful through either the viewfinder or liveview so had to just go with earlier settings and focus.

I had someone's little white dog running around in the prior image at the start. I just hoped it would keep moving at a decent rate so it wouldn't show up. Eventually the owner called it away. Dark enough even then that pooch didn't show up.

And yes, 6 minutes was starting to drag.

Last edited by southlander; 01-31-2016 at 04:32 AM.
01-31-2016, 04:55 AM   #12
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QuoteOriginally posted by bm75 Quote
Hi all. With the FF near to come, today I tested my k5 with 25 and 30 seconds long exposures at ISO 80 , just to see noise levels and color reproduction. As expected, I was REALLY pleasured by results. I was on the road to come back home, sunset war far gone, there were just the llast Iights. I shoot RAW+ , image below is jpg from camera , only resized in GIMP to be uploaded here. Obviously the image nees some tweaks in PP (consider it's JPG out of camera) but colours are really near to what my eyes have seen and noise level is so low.
It's a pleasure to rediscover every time that K5 is such a good camera! So my expectation on FF are really huge!
Best regards!
Matteo
Great shot! Iso 80 is definitely something pretty special on the K5, but it takes someone who knows what they are doing to use it correctly.

QuoteOriginally posted by Dipsoid Quote
What dictates the base iso? What stops manufacturers from enabling iso 50, 25, or even 1 on their cameras? I mean extended iso is just upping the hardware signal sensitivity, right? What prevents manufacturers from enabling arbitrarily low iso settings through firmware to enable longer exposures or to create digital neutral density filters? Would decreasing the signal sensitivity on sensor have any benefit in dynamic range? The D810's base ISO is 64, it uses the same sensor as the D800 which has a base of 100, the answer seems obvious to me, or am I wrong?

Image looks amazing by the way.
The D800 and D810 actually have different sensors. The D810 has a measured base iso of 47, while the D800 has a measured base iso of 74 (DXO Mark measurements). Nikon clearly worked pretty hard on the D810 to increase the size of the photon wells -- not a cheap proposition -- and this did give better low iso performance, although high iso performance is equivalent between the two sensors. The problem is that if you arbitrarily allow iso 25 with a sensor that has a base iso of 80 (for example), you won't increase dynamic range at all, you will just blow out highlights.
01-31-2016, 05:28 AM   #13
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QuoteOriginally posted by southlander Quote
I knew I had gone outside the 30 seconds max exposure for aperture priority shooting mode and had to go to bulb. Had tried a prior shot around 3 minutes but just darker than I wanted. I've got a reasonable gut feel these days looking at the histogram whilst reviewing images how far underexposed a image is. I took a guess at needing an extra stop or so. Started the posted image thinking about 5 minutes, then added another minute as I went along as I noticed the remaining light was fading away even as I was exposing this shot.

Once you get to long exposures like this, jumping from 3 minutes to six is only one stop additional exposure!

I could have potentially opened up the aperture to cut the exposure time but I knew from earlier images taken while in reasonable light that f8 or thereabouts gave the DOF I needed. By the time I started the posted image I couldn't see anything useful through either the viewfinder or liveview so had to just go with earlier settings and focus.

I had someone's little white dog running around in the prior image at the start. I just hoped it would keep moving at a decent rate so it wouldn't show up. Eventually the owner called it away. Dark enough even then that pooch didn't show up.

And yes, 6 minutes was starting to drag.
Great! Which kind of shooting trigger have you used? Radio trigger or the cable release? Such long exposures are not usual in my photography and I would like to experiment.
02-06-2016, 12:08 PM   #14
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iso 80 on k-5

Does shooting @ iso 80 gives you any advantages in terms of dynamic range? (RAW)

EDIT:

NEVER MIND~! I have found my answer here:
https://www.pentaxforums.com/forums/115-pentax-k-5/306993-extending-iso-range-80-a.html

In short, it does.

Last edited by tgchan; 02-06-2016 at 12:21 PM.
02-07-2016, 05:44 AM   #15
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I think the advantages of Iso 80 are more related with less noise and better color rendition (in harsh light condition I also appreciate the possibility to decrease the Iso to save exp. T ). I'm not sure there's so much difference in DR between Iso 80 and, i.e., 100 . I use the lowest Iso I can so Iso80 is a plus, but some people would never use it.
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