Effect of ISO on detail capture

Trying to isolate the parameters that affect detail (primarily the difference between detail in natural light shots vs flash). Normally natural light shots are taken at Highish ISO and fairly open apertures.
This test was just to look at the effect of ISO on detail capture with the other parameters fixed. All shots taken in manual mode with my 20D/MPE-65 F8, 1/200th with flash. Processed with my normal processing route which includes a light de-noise and USM sharpening in PS.
Conclusion using high ISO does not necessarily stop high detail capture. Think any differences are more to do with my focusing ability.

ISO100

ISO200

ISO400

ISO800

ISO1600

Thanks, Brian, for the research on iso setting and impact on detail in photos. I'm quite surprised at how little noticeable difference there is on the pics at this size. Is there significant difference in the detail in these photos when viewed at 100%? I must venture above 100 & 200 iso more in the future.

WesDigi wrote in post #3972470
Thanks, Brian, for the research on iso setting and impact on detail in photos. I'm quite surprised at how little noticeable difference there is on the pics at this size. Is there significant difference in the detail in these photos when viewed at 100%? I must venture above 100 & 200 iso more in the future.

Viewing the ISO100 and 1600 shots at 100% in PS there is no significant difference in the detail level but there is not suprisingly slightly more noise noticeable in the BG of the ISO1600 shot.

Brian V.

Every time you changed your ISO the duration of your flash dropped in half -the "virtual shutter" got faster. So getting a sharp image should have been easier at ISO 1600 than at ISO 100 if you are hand holding (or using your bean poll).

I think that ISO noise also depends on the camera that you use. With the Xti and it's smaller pixels I don't like shooting above ISO 400, and I use to use the 20D so I know it produces images that have less noise at high ISOs.

I'll probably be upgrading to the 40D -early reports suggest that it has high ISO noise performance that's as good as the 5D all the way up to ISO 800...

Dalantech wrote in post #3972575
Every time you changed your ISO the duration of your flash dropped in half -the "virtual shutter" got faster. So getting a sharp image should have been easier at ISO 1600 than at ISO 100 if you are hand holding (or using your bean poll).

I think that ISO noise also depends on the camera that you use. With the Xti and it's smaller pixels I don't like shooting above ISO 400, and I use to use the 20D so I know it produces images that have less noise at high ISOs.

I'll probably be upgrading to the 40D -early reports suggest that it has high ISO noise performance that's as good as the 5D all the way up to ISO 800...

Thanks for the comments John
I agree this is camera dependent but I was slightly suprised that there did not seem to be a loss of detail. I don't flash duration had any effect in these shots, but if it does it's benefial .

BTW I'd wait for some more in depth reviews on the 40 D and high ISO noise - I've now seen one report saying it is as good as the 5D and two reports indicating it's no better and possiblty worse than a 20D.

Brian V.

LordV wrote in post #3972635
BTW I'd wait for some more in depth reviews on the 40 D and high ISO noise - I've now seen one report saying it is as good as the 5D and two reports indicating it's no better and possiblty worse than a 20D.

Brian V.

I'm waiting for the smoke to clear

Interesting post Brian - as John has said, it's camera dependant. Try this experiment with a 7 year old 1D and you won't be nearly as impressed Secondly, you've used the high ISO with flash, which in my eyes removes the reason for using the high ISO in the first place. Whilst John is right that the amount of flash duration is decreased, the shutter speed is still 1/200 second, and that will dictate possible camera shake/lack of sharpness, so there's no real benefit in shooting at high ISO imho.

Another thing from my experience, is that with higher ISOs, you really do need to make sure that you nail exposure, preferably exposing to the right, otherwise the higher noise levels in the higher ISOs are just accentuated even more.

The only real advantage of higher ISOs imho is when shooting natural light shots without flash, or possible AV mode with flash fill in order to avoid camera shake. With natural light shots and high ISOs, there is a significant loss of detail imho, at least with the 1D (the D60's noise performance is worse than the 1D's imho).

I had planned to one day get the 1D Mark III (that's out the window now, at least for a long time lol) and shoot exclusively natural light shots without flash, relying on the good high ISO noise performance to not rob the image of fine detail.

The 1D Mark IIn is doable at ISO 1600, 1/125 f5.6, although the lack of DOF is limiting, and the slowish shutter speed generally leads to mild camera shake (at least with my heavier Sigma 150 lens, might be better with a lighter/smaller lens like the Canon 100mm etc). As long as the image is not underexposed, the 1D Mark IIn delivers amazingly low noise images at ISO 1600 imho. I'm not sure how it compares to the 20D/30D etc, but I would take it fairly well. The other drawback is that you generally have to be shooting in bright midday conditions to get enough light to shoot high ISO shots without flash, and that light is rather harsh and ugly in the shots.

Just my 2.2c worth

Dave

dpastern wrote in post #3975329
Whilst John is right that the amount of flash duration is decreased, the shutter speed is still 1/200 second, and that will dictate possible camera shake/lack of sharpness, so there's no real benefit in shooting at high ISO imho.

Depends on how close you get to the ambient exposure as you increase the ISO. If you can stay at -2 EV or lower (more under exposed) then the flash duration is your shutter speed -the fact that the camera is set to 1/200 of a second is irrelevant

dpastern wrote in post #3975329
Another thing from my experience, is that with higher ISOs, you really do need to make sure that you nail exposure, preferably exposing to the right, otherwise the higher noise levels in the higher ISOs are just accentuated even more.

Agreed: Under exposing at ISO 100 is often a good thing -but shooting under at ISO 400 just leads to more noise...

dpastern wrote in post #3975329
The only real advantage of higher ISOs imho is when shooting natural light shots without flash, or possible AV mode with flash fill in order to avoid camera shake. With natural light shots and high ISOs, there is a significant loss of detail imho, at least with the 1D (the D60's noise performance is worse than the 1D's imho).

IMHO the only advantage to shooting at a higher ISO than 100 when using flash as the primary light source (manual mode) is to decrease the flash duration to freeze motion. When shooting in aperture or shutter priority I usually set the flash to second curtain sync so that the flash is the last light source to hit the sensor -makes for sharper images.

dpastern wrote in post #3975329
*Snip*

The other drawback is that you generally have to be shooting in bright midday conditions to get enough light to shoot high ISO shots without flash, and that light is rather harsh and ugly in the shots.

...or get use to shooting with a small depth of field in early morning, late evening, or overcast days. Getting maximum depth of field is highly over rated in all photographic disciplines, including macro and closeup photography. It's not uncommon for me to go shooting butterflies on overcast days with the camera set to aperture priority and F5.6 -more than enough depth...

ISO 200 and F5.6 (shutter speed was set by the camera at 1/640):

HTTP response: 404 | MIME changed to 'text/html' | Byte size: ZERO

dpastern wrote in post #3975329
Secondly, you've used the high ISO with flash, which in my eyes removes the reason for using the high ISO in the first place. Whilst John is right that the amount of flash duration is decreased, the shutter speed is still 1/200 second, and that will dictate possible camera shake/lack of sharpness, so there's no real benefit in shooting at high ISO imho.

Just my 2.2c worth

Dave

Good point. Also, when using a TTL flash, soothing at high ISO will have an effect on the background, and not on the main subject, IMHO.

dpastern wrote in post #3975329
Interesting post Brian - as John has said, it's camera dependant. Try this experiment with a 7 year old 1D and you won't be nearly as impressed Secondly, you've used the high ISO with flash, which in my eyes removes the reason for using the high ISO in the first place. Whilst John is right that the amount of flash duration is decreased, the shutter speed is still 1/200 second, and that will dictate possible camera shake/lack of sharpness, so there's no real benefit in shooting at high ISO imho.

Another thing from my experience, is that with higher ISOs, you really do need to make sure that you nail exposure, preferably exposing to the right, otherwise the higher noise levels in the higher ISOs are just accentuated even more.

The only real advantage of higher ISOs imho is when shooting natural light shots without flash, or possible AV mode with flash fill in order to avoid camera shake. With natural light shots and high ISOs, there is a significant loss of detail imho, at least with the 1D (the D60's noise performance is worse than the 1D's imho).

I had planned to one day get the 1D Mark III (that's out the window now, at least for a long time lol) and shoot exclusively natural light shots without flash, relying on the good high ISO noise performance to not rob the image of fine detail.

The 1D Mark IIn is doable at ISO 1600, 1/125 f5.6, although the lack of DOF is limiting, and the slowish shutter speed generally leads to mild camera shake (at least with my heavier Sigma 150 lens, might be better with a lighter/smaller lens like the Canon 100mm etc). As long as the image is not underexposed, the 1D Mark IIn delivers amazingly low noise images at ISO 1600 imho. I'm not sure how it compares to the 20D/30D etc, but I would take it fairly well. The other drawback is that you generally have to be shooting in bright midday conditions to get enough light to shoot high ISO shots without flash, and that light is rather harsh and ugly in the shots.

Just my 2.2c worth

Dave

Hi Dave - appreciate the points you are making but this was just part of my attempt to understand the differences between natural light and flash shots that I thought worth sharing.
It was part stimulated by my own shooting but also by some pics from a 40D camera at 800 ISO which had good detail in them and low noise. I then realised that the 40D pics were with fill flash.
I already suspected that the main reason for lack of detail in natural light shots was not down to high ISO noise but just wanted to prove it.

The reason for the interest is that if possible I like to get natural light into my flash shots if possible by shooting in manual with the exposure only about 1 stop underexposed. This result encourages me to try using much higher ISO settings (I normally do not go above ISO 200 for flash shots) thus extending the range of times when I can do this.

John - depends entirely on what you are trying to achieve, as mentioned above I like to get a reasonable amount of natural light in my shots if possible when using flash- using higher ISOs with flash will enable me to do this more often.

Brian V.

LordV wrote in post #3976248
The reason for the interest is that if possible I like to get natural light into my flash shots if possible by shooting in manual with the exposure only about 1 stop underexposed.

I've tried that in the past Brian but wasn't happy with the way it shifts the color in my images. I'd have to do a custom white balance adjustment on every photo and even then sometimes I just can't get the color right. To add insult to injury; in aperture priority shooting at one stop under is no different than shooting at zero EV in terms of stopping motion. You might get more depth of field, but the shutter speeds still have to be relatively high. Setting the flash to second curtain sync helps, but it's still not enough to keep motion blur from being a problem.

If all you really want to do is document a critter then issues like white balance are mute unless you want to be accurate about the color of the subject...

Dalantech wrote in post #3976280
I've tried that in the past Brian but wasn't happy with the way it shifts the color in my images. I'd have to do a custom white balance adjustment on every photo and even then sometimes I just can't get the color right. To add insult to injury; in aperture priority shooting at one stop under is no different than shooting at zero EV in terms of stopping motion. You might get more depth of field, but the shutter speeds still have to be relatively high. Setting the flash to second curtain sync helps, but it's still not enough to keep motion blur from being a problem.

If all you really want to do is document a critter then issues like white balance are mute unless you want to be accurate about the color of the subject...

I'm not too worried about stopping motion but do appreciate concerns on colour rendition. Viz shots below all at ISO800.

Brian V.

Natural light

Fill Flash

Full flash

Try doing an auto white balance adjustment on the flash shot and see how it compares to the natural light shot. As you've presented them I actually like the full flash image better (the result of the light your getting from your diffuser). But it's a little dark and adjusting the levels will lighten it a little. You could also decrease shadows by about 5 to 10 percent as well.

Thanks for starting this thread Brian -lots to see and learn here

Brian - like you, and others (notably, Andy - pxl8), I prefer natural lit shots without flash. The shots just look more, well, natural imho. The series of shots that you've posted are all nice, but I honestly prefer the natural light shot, it just seems more natural on the eye. Of course, shooting with natural light is a lot more restricting as we all know...

John - I don't mind using shallow DOF, not everything is about a huge DOF imho, and a shallow DOF quite often helps isolate the subject. You'll see that I've used that technique quite a fair few times

Flash is just generally easier to use in most instances, and I think that's why we use it mostly. AV + flash is something I've started experimenting with more, and it has potential, providing you can get the fill flash balance right, and diffuse properly. I'm still learning how to diffuse the light more effectively, it's one of the things that I'm very unhappy about (in terms of my 'performance').

Brian - the newer cameras do let you do more with high ISO, they are SOOOOO much better! I reckon you can probably get away with AV mode, fill flash and larger apertures and higher ISOs and have acceptable levels of sharpness and noise, providing the ambient light is high enough of course. Australian sunlight is rather harsh for most times of the day, when it is softer (morning/evening), the light levels drop by a few stops, making it even harder to get the images.

I'd rather have Canon making a full frame 6mp DSLR with large pixels that really drop the noise down, especially at higher ISOs, than a 22mp beast like the Mark III. Sadly, marketing denotes technology, not the technology itself. Imagine a 6mp, full frame, CMOS sensor with the latest sensor technology from Canon, it would be wonderful! Add a MPE-65 to that beast, so you don't have to crop and lose resolution due to pixel peeping and voila, a nice macro camera it would be imho.

Dave

really interesting Brian I would have expected some loss of detail at higher ISO
Do you see any difference between the 20D and 350D at ISO 800 ?
of the fly shots the fill flash is really nice the flash adds some detail lost in the shadow in the natural light shot.
Pete