[beholder3]

Another interesting observation is Pentax engineers' skill in providing us ISOless sensors, meaning sensors, where you basically have no need/advantage to use higher ISO settings to provide better shadow image information in darkness.

Even in October 2020 there is not a single FF sensor out there which can compete on even ground with the Pentax K-1:

Shadow Improvement of Photographic Dynamic Range versus ISO Setting

In this graph you can see how quickly other sensors drop the ball and urge the RAW photographer to use higher ISO settings since just adjusting this in post will provide worse results.

On a K-1 all the way to highest potential ISO settings you will get pretty much exactly (ignoring 1/5 of stop differences) the same results by just going with ISO 100 and it's great dynamic range in highlights.

A K-1 raw shooter can just weld the ISO setting to ISO 100 for any and all shooting situations and will not get bad results in shadows/darkness while still retaining full dynamic range (each stop higher ISO setting steals one stop of highlight dynamic range).

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Last edited by beholder3; 10-23-2020 at 06:32 AM.

[Lord Lucan]

I thought that the K-1 uses the same sensor as the Nikon D810, and that it is made by Sony.

[house]

I compared the r5 with the K-1 using dpreview widget and noticed the same thing. Quite incredible really. If its IQ you're after the k-1 is hard to beat. Considering I bought mine new for ~$1100 I just don't know what to say.

[beholder3]

I thought that the K-1 uses the same sensor as the Nikon D810, and that it is made by Sony.

It is quite obvious that "the same sensor" doesn't mean a thing, as there still can be big differences in noise, dynamic range etc. In the end it is the image results that count.

Go compare D800, D810 and K-1 and K-1 II and you'll see quite substantial differences.

[normhead]

Exactly the point, for those of us who'e always said "Forget the frills, it's all about the image."

[MossyRocks]

But according to the canon, nikon, and sony shooters I need to get rid of all my Pentax gear and immediately switch to one of their mirrorless cameras others wise I won't be able to take a nice picture of anything. Especially for doing astrophotography. While I don't have a K-1 and am using the old K-3 I still manage, I'm hoping the rumors/speculation of the K-new sensor are true as that would be a major improvement over what I have.

The funny thing is I've been accused of faking some of my single astro shots because "there is no way you couldn't get that without an equatorial" and "there is no way your 400/2.8 is that sharp wide open".

[Merv-O]

This is why RICOH should continue the Pentax brand and market it a bit more. Pentax to me is my go to kit when I want to shoot in extreme conditions. Weather proof and fast with a superb 37mp+ sensor, et al. Even in the twilight age of Single-Reflex cameras, there is still relevance in a tank-like built SLR that delivers.
I had the K-1 Mark II, but preferred the K-1 sans the filter. Both units are wonderful and I appreciate fellow users on this forum demonstrating their enthusiasm for the K-1 series.

[dms]

I agree Pentax are mostly isoless (e.g., the K_5 and K-1), but I also think the way the data is plotted it makes small differences ("wiggles") in data seem to have too much import.

E.g., looking at DR versus iso for Nikon 810 vs Pentax K-1, they are very similar in trend for iso above 100, so that effectively the 810 is isoless. We likely don't really care about small changes (e.g., tenths of a stop) in DR.

[UncleVanya]

Isoinvariant sensors were used in a lot of cameras when Sony was mostly creating these as normal practice. I'm unclear why the latest sensors aren't following this path, but I'm order to use the latest Sony sensors these companies are being pushed away from this.

[GUB]

I hate to say it but I don't quite understand what the graph is trying to show here and I am one who constantly uses Iso-invariance. And to pop your bubble pan down the right hand box and select the K-1 ii

[Ian Stuart Forsyth]

In this graph you can see how quickly other sensors drop the ball and urge the RAW photographer to use higher ISO settings since just adjusting this in post will provide worse results.

One of the problems is that newer sensors is not that they drop the ball as you would say, They implement a new sensor design that limits how much the sensor will produce noise as you increase the iso. Dual Conversion Gain introduced by Aptina and licensed to Sony
https://www.photonstophotos.net/Aptina/DR-Pix_WhitePaper.pdf

I for one would what this in every camera that I own as it allows me to set the camera as to how I can get the best IQ for the light level I am shooting at.

Isoinvariant sensors were used in a lot of cameras when Sony was mostly creating these as normal practice. I'm unclear why the latest sensors aren't following this path, but I'm order to use the latest Sony sensors these companies are being pushed away from this.

One of the reasons is that there is a added benefit to the user of these sensors, think of this technology Dual Conversion Gain as having a switch in the camera that can give you 2 different Isoinvariant setting on your camera one being for time that you what to use the FWC of the sesnor and the other when you are only using a small portion of the FWC and having the ability to select the best time to use it.

Think of the DCG as having a bucket with another bucket attached to the side of it with a valve you can turn on and off.
Think of noise as the as food coloring sitting on the bottom of you bucket and when you have a large exposure and fill that bucket full of water there is little impact on how much that coloring will tint the overall color of the bucket. Now when we use a smaller exposure by 1/16 of the size ( where most cameras implement DCG) we are only filling that bucket 1/16 full and now that tinting can be seen in our images.

With DCG we still are able to have the same size of FWC with that same amount of food coloring but divided into 2 buckets, when we are not using the FWC of the sensor we can switch off the valve and not use that additional FWC of that second bucket that gives us the ability not contaminate our image with the additional food coloring ( noise ) from that second bucket.

DCG is literally a switch that can control how much noise the sensor will produce and allow the user to select it based on the exposure they want to use

We have had ISO invariant even in the pentax K10d
https://www.photonstophotos.net/Charts/RN_e.htm#Nikon%20D800_14,Nikon%20D850...ntax%20K10D_12

[totsmuyco]

The Pentax image quality is hard to beat. It's just that other systems market their products better. Of course the major weakness of Pentax is AFC. That's where other so called reviewers put emphasis to bash Pentax.

I'm still a child compared to some of you when it comes to Pentax. I just joined Pentax last 2014 after researching for a system to transfer to from Olympus. I didn't see much marketing then and even now. All I knew was Pentax was one of the brands in the 80s. My research led me to Pentax. Ricoh should improve on its marketing strategy to encourage new users.

[Rondec]

I hate to say it but I don't quite understand what the graph is trying to show here and I am one who constantly uses Iso-invariance. And to pop your bubble pan down the right hand box and select the K-1 ii

The K-1 II has the accelerator chip which you see kick in at iso 640. Since the chip isn't doing anything below iso 640, you could shoot at those isos and have the same performance as the K-1. At higher isos, the accelerator chip is working on the RAW data, trying to clean it up some, hence the graph that you see there.

[beholder3]

Dual Conversion Gain

DCG is a poor and severly limited patch for sensor problems which a Pentax K-1 does not have.
Simply speaking for Raw shooters it just brings one specific ISO setting up to the dynamic range performance which base ISO provides.
A fully ISO-invariant sensor such as the Pentax K-1 sensor has no need for this problem-patching by DCG at all since you can fix ISO 100 in the camera and loose nothing.

A pretty obvious example of the poorness of DCG is a comparison D7200 (ISOinvariant, no DCG) vs A6300 (ISOdependend, with DCG patch):

Here we see that the Sony has DCG activated for ISO 400, while the Nikon has nothing:

Read Noise in DNs versus ISO Setting

Here we see that DCG effectively is a wasted effort without any advantage versus the ISOinvariant design even if the user adjusts ISO:
Photographic Dynamic Range versus ISO Setting

And here we see that the Sony DCG sensor actually requires the user to crank up ISO and can not achieve the same results by just pulling up shadows in post, while the D7200 user has no need to care for ISO:
Shadow Improvement of Photographic Dynamic Range versus ISO Setting

I want a K-1 style ISOinvariant sensor if I can get one (probably not). Anything else is worse with regards to image quality, as can be seen by the newer and worse sensors.

[automorphism]

The Pentax image quality is hard to beat. It's just that other systems market their products better. Of course the major weakness of Pentax is AFC. That's where other so called reviewers put emphasis to bash Pentax.

While I agree the Pentax image quality is good...so is every other camera system. There might be slight differences in sensors but a D750 or a K1 or an R or an A7iii...there is not much point in choosing a system based on sensor image quality. They are are superb.