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Author Topic: Please give us ISO 25, 12, 6...  (Read 1657 times)
Deardorff
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« on: May 14, 2014, 05:31:08 PM »
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Please camera makers. Give us slow ISO settings.

Way too much neutral density necessary to get long exposures in daylight at ISO 100 and 200 without stopping down too much.

Give us ISO settings with high quality to compare with Kodachrome 25 and Kodak Tech Pan at 6 or 3.

Would enable longer esposure times in daylight for motion effects and landscape work.

One place where film still does a very good job.
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DeanChriss
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« Reply #1 on: May 14, 2014, 05:41:27 PM »
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Indeed. It's not always about fast shutter speeds. I'm not sure if it's easy for camera makers to do this, but I do know the DR of my cameras (Canon) is reduced if I set them to ISO 50. Regardless, I'd welcome a wider ISO range at the low end.
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BJL
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« Reply #2 on: May 14, 2014, 07:24:58 PM »
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Please camera makers. Give us slow ISO settings.

Way too much neutral density necessary to get long exposures in daylight at ISO 100 and 200 without stopping down too much.

Give us ISO settings with high quality to compare with Kodachrome 25 and Kodak Tech Pan at 6 or 3.

Would enable longer esposure times in daylight for motion effects and landscape work.

One place where film still does a very good job.
With electronic sensors, lower base ISO speed mainly just means less sensitivity; it does not come with the trade-off of finer resolutuon the way it does with finer grained film. So the only likely way to get lower sensor speeds is by use of ND filters, or for a similar effect, taking several frames in (rapid?) succession with different exposure times and blending them. Yes, there are other options, like one that Fujifilm tried with its CCDs, effectively mixing faster and slower photosites, but if anything those methods reduce resolution in exchange for greater dynamic range.

P. S. One advantage of EVFs OVER OVFs is that you can use a strong ND filter and still be able to see through the VF.
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Fine_Art
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« Reply #3 on: May 14, 2014, 08:12:43 PM »
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Why can't you average several frames to get the ND filter effect?
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EricV
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« Reply #4 on: May 14, 2014, 08:50:07 PM »
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The problem you are trying to solve is too many photons, filling the sensor pixels to full capacity with a short exposure.  The ISO knob only controls electronic amplification of that signal after the photons have already been collected, hence does not address your problem.  The only practical solution, with most current sensor designs, is to reduce the number of photons hitting the sensor.
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Fine_Art
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« Reply #5 on: May 14, 2014, 08:56:09 PM »
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The problem you are trying to solve is too many photons, filling the sensor pixels to full capacity with a short exposure.  The ISO knob only controls electronic amplification of that signal after the photons have already been collected, hence does not address your problem.  The only practical solution, with most current sensor designs, is to reduce the number of photons hitting the sensor.

I said average, not add. I can add frames, which will blow out anything on the right side of the histogram. I can average frames which will not blow it out, it will have the same effect as 50% opacity in layers. So unmoving things stay looking the same, moving things get motion blurred. That is the effect you are after with a long shutter speed.
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EricV
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« Reply #6 on: May 14, 2014, 09:25:47 PM »
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I said average, not add.
  I was responding to the original poster, who wanted an ISO knob.  Your suggestion to average images is a perfectly good solution to his problem.
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BJL
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« Reply #7 on: May 15, 2014, 09:59:24 AM »
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Why can't you average several frames to get the ND filter effect?
No reason that I can see; actually that is a lot like my suggestion. You could average several frames with equal exposure time, but it might be preferable to use frames of different exposure times, to handle shadows and highlight with less total frames needed.  For example, two frames at 1/400 and 1/100 could give results a lot like five frames at 1/400, but with less shutter vibration to deal with and less total time required.

But perhaps if the goal is the artificial artistic effect of massive motion blurring, a single uninterrupted frame taken through an ND filter works better.
« Last Edit: May 15, 2014, 02:19:06 PM by BJL » Logged
SZRitter
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« Reply #8 on: May 15, 2014, 10:09:01 AM »
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But perhaps if the goal is the artificial artistic effect of massive motion blurring, a single uninterrupted frame taken through as ND filter works better.

I was actually trying this one day to see which looked better. The test was done with a flowing river with some small rocks causing minor breaks and white water. The ND came out much smoother than multiple images stacked together and then averaged using either median or mean averaging. Personally, I am all for the stacking multiple ND filters as it gives smoother motion.

However, if you were trying to use the slower shutter speed to "erase" moving objects from a frame, then I would be all for the multiple exposures.
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EinstStein
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« Reply #9 on: May 17, 2014, 09:39:12 AM »
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Easy, just get the ND filter.
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scooby70
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« Reply #10 on: May 19, 2014, 05:27:01 PM »
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Yup, and then spend your life juggling ND filters and holders and lens hoods etc.

I hate this... I realise that I need to slow the shutter speed down so I take my lens hood off and put it in my pocket and then I get the ND case out of my pocket or bag and remove the ND from the case and fit it to the lens and then I shoot... and then I realise that for the next shot my ISO is too high and / or my shutter speed is too low and the ND has to come off so I get the case out and remove the ND from my lens and place it in its case again and put it back in my pocket or bag.

It may seem a small thing but some days I need to do this for maybe one shot in three and it is IMVHO a right royal PITA and one of the worst things about shooting digital and living with the seemingly ever rising base ISO's.
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BJL
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« Reply #11 on: May 19, 2014, 06:16:32 PM »
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Scooby70: if you are pining for the lower minimum ISO speeds of older sensors or even film, there is a simple way to reproduce that: leave a suitable ND filter on all the time.

Because the only thing that made minimum ISO speeds lower in the past was lower sensitivity to light, and their maximum usable ISO speed was lower by even more (due to more noise), so that an ND filter on a modern sensor can match the low minimum speeds of yore while still allowing better low light handling.  The only time that you would need to fiddle with putting an ND filter on and off is to get better low light handling that those earlier sensors (or film) offered.  So I do not buy this "things were better in the good old days" line.

Nevertheless, it would be even better to have an internal switchable ND filter, like some compact cameras already have.
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EinstStein
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« Reply #12 on: May 19, 2014, 10:25:29 PM »
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Face it, you are not going to get the sensor at ISO 25 or lower. Like it or not. Period.
If you really can't live without the extreme wide angle with extreme slow speed, ND is your only choice. 
It's up to you. Denial won't get you anywhere.
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scooby70
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« Reply #13 on: May 20, 2014, 04:30:54 PM »
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Scooby70: if you are pining for the lower minimum ISO speeds of older sensors or even film, there is a simple way to reproduce that: leave a suitable ND filter on all the time.

Because the only thing that made minimum ISO speeds lower in the past was lower sensitivity to light, and their maximum usable ISO speed was lower by even more (due to more noise), so that an ND filter on a modern sensor can match the low minimum speeds of yore while still allowing better low light handling.  The only time that you would need to fiddle with putting an ND filter on and off is to get better low light handling that those earlier sensors (or film) offered.  So I do not buy this "things were better in the good old days" line.

Nevertheless, it would be even better to have an internal switchable ND filter, like some compact cameras already have.


Things were not better in the olden days if we're talking the 1950's. I'm staying with a digital camera thank you and no, using a modern sensor at ISO 1600 in daylight to overcome the ND just isn't the answer I'm looking for.

The problem with having an ND on all the time is when you point the camera in a direction which causes your shutter speed to drop and your ISO to rise. When that happens the filter has to come off and as I said for me it tends to be on for maybe one shot in three and personally I find swapping ND's on and off to be a pain for discrete hand held shooting.

Thankfully my A7 has ISO 100 as did my Canon DSLR's but sadly many CSC don't have it and have a base ISO of 200 and possibly a max shutter speed of 1/4000 making ND's even more of a requirement if you like shooting at wider apertures in decent light and of course if you are a fan of shallower depth of field you'll possibly be shooting at wider apertures more often with a MFT or APS-C CSC than you would with a FF camera.

Of course if you are happy to shoot with your widest aperture being maybe f5.6 you may never need an ND filter even in good light. Problem solved. Or you can leave an ND on all day and shoot at ISO 1600-3200. Again, problem solved.

But not in a way that suits me Cheesy
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BobShaw
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« Reply #14 on: May 20, 2014, 05:06:24 PM »
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Agree with the poster. ND filters are not a good solution because they darken the view. I have minimal interest in high ISO for most of my work.
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BJL
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« Reply #15 on: May 20, 2014, 05:49:11 PM »
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Agree with the poster. ND filters are not a good solution because they darken the view.
That's not so much of a problem, on an EVF camera like the A7, since the EVF's brightness can be adjusted up.
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BJL
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« Reply #16 on: May 20, 2014, 06:17:53 PM »
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The problem with having an ND on all the time is when you point the camera in a direction which causes your shutter speed to drop and your ISO to rise.
I know: what I was saying is that even is this higher ISO situation, you are no worse off than with those older, lower ISO sensors, due to the improved usability of the newer sensors at higher ISO speeds being enough to off-set the light loss due to an ND filter.  For example, the changes that move minimum ISO speed from 50 to 100 (improved QE through BSI, better micro lenses, etc.) also mean that ISO 800 is as good on the new sensor as ISO 400 was on the old, and so on up.  (Probably a bit better in fact, due to other improvements that do not raise the minimum ISO speed.)  So even if you use a 1 stop ND filter to emulate ISO 50 when set at ISO 100, so that you need to use ISO 800 where the older sensor would have needed only ISO 400, you are no worse off than with that older sensor.  It is just that to both
(a) get the low light performance advantage that the newer, more sensitive, sensors have over the older ones and also
(b) be able to handle "very low exposure index" situations
requires the extra fiddle of putting an ND filter on and off.

Of course it would be very strange to use a camera with always-on ND filter, but even that weird usage would be better, not worse, than using one of those older, less sensitive sensors, at least with an EVF that can adjust the viewfinder image brightness for the presence of an ND filter.

P. S. Another little bit of good news: with some recent cameras, like Olympus CSCs, the base ISO speed (minimum safely usable exposure index) is significantly lower than the minimum setting on the ISO dial: they are calibrated to give more raw highlight headroom than the minimum suggested by the ISO 12232 standard.  So a camera like the EM5 with a minimum ISO dial setting of 200 has a minimum safe exposure index of about 120-130.
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PeterAit
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« Reply #17 on: May 21, 2014, 07:09:26 AM »
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Yup, and then spend your life juggling ND filters and holders and lens hoods etc.

I hate this... I realise that I need to slow the shutter speed down so I take my lens hood off and put it in my pocket and then I get the ND case out of my pocket or bag and remove the ND from the case and fit it to the lens and then I shoot... and then I realise that for the next shot my ISO is too high and / or my shutter speed is too low and the ND has to come off so I get the case out and remove the ND from my lens and place it in its case again and put it back in my pocket or bag.


It's a lot simpler if you keep your breast pocket clean and just stick the filter, sans case, in there. Then you can just remove the hood with one hand, grab the filter and put it on with the other, and back on goes the hood.
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Peter
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