Rob Trek Forum

I am working on an interesting article which I believe can help M43 photographers. I placed a preview on my blog and invited readers to come over here to discuss. That's the reason for placing this discussion...

https://myolympusomd.blogspot.com/2021/ ... d-l64.html

Any thoughts?

Siegfried

I think this will be a great topic for one of my live streams. Maybe you could even join in as a guest!
I like the exercise you suggested as this is really a great way hands-on way to teach the subject.
That said, you're opening up a can of worms here. Meaning, this is a very small piece of a much larger topic on exposure and IQ.
Maybe I'm getting ahead of myself. I'll sleep on this and get back to you here.
Thanks as always for sharing your knowledge.

Thanks for your input, Rob. I look forward to discussing this off-line with you, and I will wait for your lead...

You are 100% right in terms of the complexities of the subject. The secret is to stay factual and to present only credible info. I spent hours on research plus my engineering background helps me. My presentation style is specific and it seems to work as photographers seem interested and the reaction to my most recent articles really good.

I find it difficult to present something this "different" in comparison to the existing "acceptable" bigger picture. For example, I am having a hard time structuring my follow-up article or part 2. The reason is twofold, on the one hand, I am discussing different and new information targetted at digital cameras, and on the other hand, I am asking photographers to re-evaluate their existing photography space and to consider a different and updated bigger picture. I hope this helps..?

For example, I am not biased for or against any format. A while back my son visited us and placed a new Sony A1 with f1.4 prime in my hand. It was evening, dimmed lights and I turned and took a portrait image of my wife. I was completely surprised by the A1. The challenge is not everyone has the +6K to spend on only a camera body. What about the person with an EM10 II, who paid $150 secondhand? In a previous example, my son and I were doing product photography and I learned just how much noise the A7RIV images have. How do we learn from these "inconsistencies" and how do we apply what we learn to improve the performance of our own cameras?

The positive is, the right information benefits ALL photographers. What is the best way to present it?

I like to encourage readers to do the challenge on my blog and to recreate the 3 illustrations, I posted.

Siegfried

I did reply on your blog. The reason some people do not like low ISO is that you have to get it right and have less exposure latitude. And for most people that is not worth the better photo. Which all has to do with what Olympus does between the sensor and the raw we get to work with.

While I worked on part 2 on the series ISO and IQ, I noticed some mistakes I made in another article on Sensor Sensitivity. As I updated that article I realized the challenge in the ISO and IQ article is maybe too advanced, especially when it's the first time you do something like that.

The reason is, the image sensor and the ISO has to be managed separately. With the third illustration in the same article, you need to use an external light source. (similar to ETTR) That means we are talking about several ways to control image noise and the digital camera. Exciting news don't you think?

See the latter part in the article on sensitivity for more on how to manage the image sensor and the ISO separately...

I hope this helps as nobody came up with an answer to date...

Siegfried

Again I commented on your blog. I think it gets beyond what people reading on this site may be ready for. If you drink, I would love to sip good Bourbon and talk for hours about this and other things of this nature.

Hello DeMorcan, again thank you for your input. I really appreciate it. I posted the same reply as below on my blog. Yes, I love to chat with a Gin and Tonic, my wife is tired of me testing and non-stop talking about this interesting subject...

I think your concern is linked to you probably over-designing these examples. We basically have a sensor with a native sensitivity and a once-off factory sensor gain adjustment to make the sensor compatible with the rest of the camera. How specifically that correction is done is not important, what's important is, sensor sensitivity, once-off correction plus the impact it has, and finally, additional gain (ISO) on gain (factory) with the ISO setting. This also explains a lot of why sensors are different...

Update:- I updated the examples with a little more info. Hope it's clearer like this... and thanks again

Siegfried

My blog reply:

I agree that the bigger picture details should be accurate, it's obvious, right? When you drill down to photocell or pixel-level things quickly get complex and of no specific value to the discussion. In fact, it's more a testimony of the fact that there is much more happening below the surface to reduce noise or improve IQ than only looking at size, right?

What is really important for me is to leave folks with a credible big picture that will help them to master their digital cameras. As you see this bigger picture article already took up a lot of space. Is the bigger picture really of value or should one just throw out the facts?

What are the takeaways?

1. If I advise someone to keep the ISO constant and to overexpose with 1 stop, what am I proposing? If you studied my articles you will immediately know I am targetting the sensor. In what conditions would I target the sensor?

2. Vice versa if I advise someone to keep the exposure and the ISO the same, but to use an external light source to over-expose with 1 stop and then do a (-1) exposure correction on the raw file in WS, what am I doing? Again if you studied my articles you will know we are not touching the sensor or the image signal amplification but I am proposing ETTR with an external light source. Why compensate in WS. Most probably because color accuracy was important...

These are the end goals I like to get to and to get there I believe the bigger picture is key. Any thoughts?

Below is the reply I posted to your post on my blog. Thank you for your support.

I think the key is as explained in my reply below. You are addressing several complex subjects in one short post. The first and most important is to separate video from photography. Agreed, the basics on exposure are similar but from there on the differences are just too big to combine in one discussion, right?

This is why Dual ISO can be so confusing when it's discussed in a photography context (My Blog) The presenter in your link wrote in his title that he is discussing video recording...

One final comment - From my experience with the A7 III, like the GH5, these cameras do not have dual ISO. The only one that seems to have dual ISO for both video and photography is the Panasonic S5. I know to little about this camera to comment unfortunately...


My reply below was to a comment DeMorcan kindly added to this article:- https://myolympusomd.blogspot.com/2020/ ... ticle.html

Hello DeMorcan

I had a look at the video (link) you included in your post. It seems the presenter was doing his presentation with reference to Adobe Premiere Pro (video editing program). I didn't get the feeling he was talking about photography.

To date, it is not possible to change the ISO in any RAW file with Lightroom, PS, or Workspace. The only time you could change the ISO in a RAW editor is with video files (I am familiar with ProRess RAW video files)

That said, you are addressing a number of parallel and different subjects. Let's take a helicopter view of video and imaging. Apart from the Panasonic S5 (with dual ISO for both photography and video), I am not aware of any other imaging camera with dual ISO capability.

We know hybrids like the GH5S, the A73SIII, and later video-specific models like the Black Magic and REDS with dual ISO.

Video:-

- One can change the ISO in post-editing with RAW video files

- The Dual ISO functionality is available with the GH5S, A7S3, BMCC, REDS & other

- From what we know 2 separate ADC (analog to digital) circuits are used

- See this video for more on Dual ISO - See the video below

Photography:-

- It is not possible to change the ISO of the raw image in any RAW Editor

- No Dual ISO available in photography - Other than the S5, I haven't seen any

- Only one ADC is used on photography with the focus on purity and IQ

- Listen carefully to the video below on ISO, steps upping the ISO and color

I trust this will answer most of your concerns...

.


Best

Siegfried

Folks my article (Part 2) is ready... I posted it today on my blog.

The answer is really simple, the focus should be amplification and not dynamic range. The first benefits photographers and the second promoters and manufacturers.

There is much more really interesting info in this article, I hope you will enjoy it...

Then I like to wish all a happy festive time and only the best for 2022

Siegfried

Happy new year guys...

I did a number of corrections and added more information to the article...

I also added an interesting test to see if there are differences in the noise floor between the EM1 II and III.

You can find it here:- https://myolympusomd.blogspot.com/2021/ ... 64_19.html

Best

Siegfried