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mas
9th April 2009, 06:22 PM
Hi,

I was reading an aside in a commentary about one of the Canons which said that the fastest ISO didn't give the best image quality. Instead it was stated that each sensor has an ISO setting which is its 'native' or 'natural' setting which would give the best quality of image.

Thinking about it I can see that that makes sense. The sensor will have an optimum position.

So. What would be the optimum ISO on a 4/3rds? Up til now I always try to have the ISO as fast as possible, only increasing it when I cant manage to handhold without shake. Should I be using a higher ISO as a matter of course?

*shrug

Archphoto
9th April 2009, 08:45 PM
The best ISO is the lowest: 100 ISO
The higher you get with ISO's the more noise you get.
I see 400 ISO as a maximum working ISO for asignments and even then I have to use Noise Ninja more than I like with my E520.

I do a lot of interior shots and rather go from f:8, the optimum aperture down to f:5.6 than go to 800 ISO.
If I can not make it with these settings I use my E410 on a tripod set at 100 ISO and f:8.

Peter

theMusicMan
9th April 2009, 09:27 PM
To be honest, who really cares what the reviews or other sites state? What I interest myself in is checking and evaluating the performance of the camera I use at the ISO settings I wish to use it at! If I am happy with the performance at whatever ISO I choose to use, then that's fine.

:)

PeterD
10th April 2009, 09:22 PM
To be honest, who really cares what the reviews or other sites state? What I interest myself in is checking and evaluating the performance of the camera I use at the ISO settings I wish to use it at! If I am happy with the performance at whatever ISO I choose to use, then that's fine.

:)

John, whilst I agree with you, I think mas was seeking some guidance in what Iso's we use the cameras at as a norm.

There are a number of solutions for dealing with the noise from using higher ISO values and the saving grace is that most of the noise produced is luminence noise which can easily be removed within say lightroom or Noise Ninja and Neat Image. Detail however may be lost in a noisy image which obviously cannot be restored. Colour accuracy also tends to also be affected at higher ISOs but his can be corrected post processing.

Given the above, I rarely have the opportunity to shoot at ISO 100 as I need a high shutter speed to capture wildlife images.

With the E3 I normally set out at ISO 400. Depending on the lighting, I may increase this to ISO 800 if necessary to get the shutter speed above 1/500 when using the Bigma. ISO 800 gives me no concern but going up to ISO 1600 can be a bit dicey.

With the E500 I normally stick with ISO 400. I rarely use telephoto lenses with this camera and it seems to give me the shutter speed I want. Lack of IS leaves me to target 1/250 for hand held shots which I find achievable for most daylight conditions.

I should also say that I shoot aperture priority and try and use the range f8 to f10. Varying this only when I want to adjust dof.

Hope it's not confusing. It would be interesting to hear the opinions of others.

Peter

MarkVarley
10th April 2009, 10:21 PM
Hope it's not confusing. It would be interesting to hear the opinions of others.


For what it's worth I always stick to 100 99% of the time (the only exception is infrared when I readily jump to 800 or 1600 right away), I will push my luck with shutterspeed having gone as wide as I dare with aperture before pushing the ISO further than 200 (most of the time).

A recent exception was a karate competition that we had to cover where the lighting was just rubbish (also had a similar thing with dance late last year), poor lighting and not allowed to use flash combined with the need to freeze movement with a fast shutter, aperture wide open and just had to ramp the ISO through the roof and do some heavy NR in post.

I have no ideas about native ISO but there is, simply, an increase in 'noise' as you increase the ISO, readily noticeable from 400 upwards.

OlyPaul
11th April 2009, 08:14 AM
I'm quite happy to use up to ISO 800 with the E-420 and E-30 as long as the exposure is correct. :)

To be honest, who really cares what the reviews or other sites state? What I interest myself in is checking and evaluating the performance of the camera I use at the ISO settings I wish to use it at! If I am happy with the performance at whatever ISO I choose to use, then that's fine.

:)

John I could not agree more especialy as some of the high ISO tests are not what they seem. ;)

http://www.pbase.com/paulsilkphotography/image/111141049.jpg

Ian
11th April 2009, 11:33 AM
I have been testing noise and resolution on the E-3, E-620 and Panasonic G1 and there is very little to choose between ISO 100 and 200. (By the way, the E-620 scores really well for resolution across the ISO range and just edges the G1... more on FTU in a few days time.)

Where there is some growing consensus is that ISO 200 is the optimun setting because people are seeing more over-saturated highlights at ISO 100 compared to when using ISO 200. It's a grey area, really. I haven't seen any evidence for the ISO 200 argument in technical tests (like DxoMark, for example).

Ian

Garrie
11th April 2009, 11:11 PM
I'm no expert by a long stretch however I always use an ISO value of 100 as I almost always shot on a tripod and 85% of the time bracket.

having said that the E1 at iso 400 in good light is mint (forgot to switch back to 100), even pseudo tonemapping from 1 raw file noise is not an issue.

crimbo
12th April 2009, 07:07 AM
While we all have our preferred settings that we work with and produce excellent results I think the original question could be framed...
If the Olympus cameras were not ISO selectable what would be their native ISO outof the box?
Like in the film days where a film had a native ASA in the standard development that was written on the box
FP4 125, Tri-X 400 etc

Barrie Norman
12th April 2009, 08:15 AM
It would be interesting to hear the opinions of others.

Peter

Peter

As we shoot the same subjects I agree with you, both with my E1 and E500's Istartt off with ISO 400 and as I am shooting "A" priority I adjust the ISO setting to give me the best shutter speed 1/500 @ f/8.0 if possible and I will use ISO 800 without any problems. Neat Image is my choice for noise removal and it works very well. But I am not an expert and it depends what subjects you are taking, and I feel that for specific advice an photographing particular subjects talk to the people who are having success in that area and dont be affraid to post your work and get advice, after all that's what this forum is about. and we will all try to give advice where we can. a closing note! dont belive all that is written go out and experiment, if you are happy with the results, thats all that matters.

theMusicMan
12th April 2009, 08:56 AM
John, whilst I agree with you, I think mas was seeking some guidance in what Iso's we use the cameras at as a norm.


Hi Peter

Sure, I guess I sort of misread the OP's thread.

I guess the ISO setting I use is dependent on the amount of ambient lighting available AND the IQ I am after. If I am totally honest, I am tending to use higher and higher ISO settings as my defaults. For example, I was out yesterday afternoon with Jen and the dogs, in bright spring sunshine, and the ISO was set to ISO400 (check the House Sparrow shots I posted recently), and I am more than happy with the results.

On the other hand, when I want to try some HDR shots, I use the lowest ISO setting I can.

mas
12th April 2009, 09:49 AM
Crimbo has pretty much nailed the question that I thought that I'd asked.

I've always tried to keep the iso as low as possible, but the comment I read made me wonder if my priorities were skewed. I think I've been pushing shutter speed too much when I should have upped the ISO. Having seen very little difference in picture quality from upping ISO, I then thought that perhaps there is a good point. And I can see (from an electronics point of view) that the 100 ISO setting - which is after all replicating something from film - may well not give the best image quality.

So I wondered if (a) olympus published any tech info which cast any light on this, and (b) if everyone just assumed that lower iso = better quality or if people had done any evaluation of this. (thanks Ian).

Barrie Norman
12th April 2009, 09:56 AM
Here is a link to test carried out on the E500 with regards to noise at ISO settings form 100 - 16000 and the effects of in-camra noise filtering and post-processing noise filtering you may find it interesting.

http://www.wrotniak.net/photo/43/e500-noise.html

Nick Temple-Fry
12th April 2009, 10:35 AM
I think we have been scared of high iso, perhaps because of all the review comments about poor high iso performance. And there is some truth in these comments, higher iso settings can be a weak point of the sensors in olympus cameras. But noise can be managed both in pp and whilst you are taking the shot.

A better shot with decent dof and good exposure at a higher iso will beat hands down a shot you've squeezed out of the camera with exposure tending to the left and a too shallow a dof (or a lens too open to be happy). And of course if you take a noisy image at iso 800, then it's hard to realise that at iso 1250 with a well balanced histogram you will actually get a better/cleaner image.

I'll regularly shoot at iso 1000 or 1250 (Canon 1600 equivalent) if it means a good shutter speed and a good exposure. So with the later sensors (at least) look at the histogram you are getting as well as the iso and the shutter speed. A good exposure opens up the higher iso values.

Nick

mike_j
12th April 2009, 12:34 PM
It does depend on the lens but very often I work at 200 ISO. This usually lets me open up the lens to f2 for DoF if necessary but is probably more because I'm comfortable with it as it was my preferred film speed as well.

PeterD
12th April 2009, 11:46 PM
I think we have been scared of high iso, perhaps because of all the review comments about poor high iso performance. And there is some truth in these comments, higher iso settings can be a weak point of the sensors in olympus cameras. But noise can be managed both in pp and whilst you are taking the shot.

A better shot with decent dof and good exposure at a higher iso will beat hands down a shot you've squeezed out of the camera with exposure tending to the left and a too shallow a dof (or a lens too open to be happy). And of course if you take a noisy image at iso 800, then it's hard to realise that at iso 1250 with a well balanced histogram you will actually get a better/cleaner image.

I'll regularly shoot at iso 1000 or 1250 (Canon 1600 equivalent) if it means a good shutter speed and a good exposure. So with the later sensors (at least) look at the histogram you are getting as well as the iso and the shutter speed. A good exposure opens up the higher iso values.

Nick

Thanks for this Nick. I knew this thread would be useful. When I first tried wildlife shots I went for shutter priority and auto ISO. The results were not too bad most of the time but using a long lens on a dullish day caused the camera to select very high ISOs with the result that I got very noisy images. In some cases, I could not deal with the noise. This put me off high ISOs. I now have Neat Image so I may try pushing up to ISO 1600 again and see what happens.

Peter

crimbo
13th April 2009, 06:07 AM
Looking at this thread I put together http://e-group.uk.net/forum/showthread.php?t=5146
I get the impression that the native ISO for the E400 is about 100ISO as colour noise appears to be introduced above that

mas
15th April 2009, 09:26 AM
Some interesting thoughts.

Crimbo, your examples certainly sem to show ISO 100 best in that example. I think I'll do some testing of my own.

In the wrotniak article it seems to me that ISO 200 is just as good. But a different situation and camera.

Anyway, I shall be more prepared to wander from the ISO 100 standard.

ndl0071
15th April 2009, 12:47 PM
An interesting thread,

I tend to keep my iso set to auto but with it 'capped' at 400 so I don't actually shoot with any larger numbers than I intend to.

This is an option on the E3 but I'm not sure about other models.:)

crimbo
15th April 2009, 04:48 PM
An interesting thread,

I tend to keep my iso set to auto but with it 'capped' at 400 so I don't actually shoot with any larger numbers than I intend to.

This is an option on the E3 but I'm not sure about other models.:)

Auto ISO in the E400 is 100ISO and only changes when flash is used...dont know if this changed for later models

Rawcoll
16th April 2009, 08:49 AM
Just to follow up on Ian's comments from a few days ago:



Where there is some growing consensus is that ISO 200 is the optimun setting because people are seeing more over-saturated highlights at ISO 100 compared to when using ISO 200. It's a grey area, really. I haven't seen any evidence for the ISO 200 argument in technical tests (like DxoMark, for example).

Ian

I see that the DP Review of the E30 shows about half a stop more usable range overall at 200ASA compared to 100ASA, with over 1 stop difference being in the highlights. This presumably would explain what folk have been finding in practice.

Anyone got an explanation for this? I guess it must have something to do with the relative amounts of sensor noise and amplifier noise, but I can't grasp why this doesn't have a greater impact in the shadows rather than the highlights.

Ian

Rawcoll
16th April 2009, 09:18 AM
A bit of Googling has revealed an answer to my own question! What I found was:

"Any digital sensor has a floor ISO sensitivity which is the readout of
the charge collected in its photon wells without any amplification.
Higher ISO settings is achieved by amplyfying the analogue readout of
photon wells. This makes the sensor appear more sensitive, but also
amplifies any noise present in the signal.

Setting ISO below this floor serves no purpose. The photon wells
will simply overflow, resulting in a reduced dynamic range."

That makes sense. The highlight range would be significantly restricted, but in setting a gain of less than one (i.e. to reduce sensitivity from the native 200ASA to 100ASA) would also reduce sensor noise as well as the signal (so long as the amplifier itself doesn't contribute much noise), and so contribute to the extended shadow 'tail' of the response curve.

Surprising what can be found on the web *yes

Ian

crimbo
16th April 2009, 04:17 PM
But do we know what these 'floor ISO's are for the Olympus sensors or are there practical tests we can do to determine them?

Rawcoll
16th April 2009, 06:29 PM
I think that the straight answer is 'no', but one could surmise from the likes of DP Review data that the base ISO for the E30 is above 100ASA. The same result is observed in the Nikon D700, D3 and D3X reviews for example, but in those cases Nikon has indicated what the base ISOs are and has prefixed slower speeds by 'L'. I can't imagine that Oly will be forthcoming on this, but Ian might be able to get some inside info. At any rate, it is perhaps sufficient to be aware that the better DR appears to occur at 200ASA and not 100ASA. What happens between 100 and 200ASA is anyone's guess.

Still, what does impress me, if DP Review's data are anything to go by, is that the E30's approach to clipping is much gentler, for speeds of 200ASA and above, than with my E510 (or even the E3 for that matter). Much more film like I think. It will be interesting to see if the E620 has the same characteristics.

Ian

Zuiko
16th April 2009, 09:58 PM
In this week's Amateur Photographer Barney Britton tests the E620 and finds that the camera has one whole EV stop of dynamic range more at ISO 200 compared to ISO 100 which leads him to believe that the native ISO is 200.

Whether this relates to all Olympus cameras I don't know, but if it does it would seem that ISO 100 is best avoided unless you particularly want to achieve the lowest possible shutter speed, for example when attempting to create some artistic blurr or subject movement.

It could also explain why other models in previous tests have revealed slightly worse DR than the competition; if the test has been conducted at ISO 100 the sensor could have been at a disadvantage of 1EV compared to how it would have rated at ISO 200.

It would also make sense to have ISO 200 as the native setting. If you think about it, noise is bound to increase with each stop that ISO is increased beyond the native value, therefore if this was ISO 100 then higher ISO values would automatically be worse than on competitor cameras with a native ISO of 200 - quite apart from any other differences in sensor performance.

Rawcoll
17th April 2009, 07:28 AM
That's good to know about the E620.

I don't think it does apply to the other models. Looking at DP Review data (for consistency if nothing else - I don't have any affiliation :)) for the E510, E520, and the E3, there is nothing to suggest that the native ISO is anything other than the lowest setting. DR isn't seen to increase as the ISO is bumped up from 100 to 200.

Interestingly, I see that the data for the G1 shows no such effect either. That means that the native ISO for the G1 sensor is 100, rather than 200. If these characteristics are indeed inherent in the sensor itself, then it does suggest that the G1 and E30/620 sensors are not as similar as might at first be thought. Also, the response characteristics of the G1 give a much more abrupt approach to clipping than does the E30, more reminiscent of my E510 (albeit with a slightly larger DR). Intriguing.

Ian