[totsmuyco]

The reason I normally hear why people avoid Pentax in my part of the woods is that the system is inferior to canikon. Inferior in terms of gimmicks and of course AF. The other reason is access to third party lenses and accessories. When I'm asked why I chose Pentax, I had to give my litany of reasons. I chose Pentax because it fits what I'm looking for. Though I wish for better AF improvements. Like others, I also wish access to third party lenses and accessories. When I bought into Pentax about 4 years back, new Sigma and Tamron lenses were still available for Pentax. So there were more choices. Now it's very limited. I guess those are the reasons why people jump ship here in my country.

Each system have their strengths and weaknesses. My advice to jumpers would be, go the system that fits your needs. But please do due diligence. It's just too costly to jump from one system to the next unless you're awash with cash. Just my thoughts

[bm75]

Each system have their strengths and weaknesses. My advice to jumpers would be, go the system that fits your needs. But please do due diligence. It's just too costly to jump from one system to the next unless you're awash with cash. Just my thoughts

+1. very true.

[sqrrl]

I personally use pentax and panasonic

Pentax because it's tough enough to survive me (my k10 got abused in the aussie outback for three years and is still mostly functional), and I have the 4-5 lenses which I consider essential personally.

Panasonic because they're small and do great video, they're also cheap a couple of years after they come out. Plus I have an olympus which kinda sits between the two.

I'm not so worried about focus speed, though the difference is more minimal then some people make out, Also not too worried about strobe control, as I tend to run manual for that.

[Nicolas06]

Yes, it could be so. But they make (Nikon for sure) many f/1.8 primes (also f/1.4) for FF. just Pentax and Fuji make beautiful primes for APSC. So..shooting APSC Pentax has a strong value with a consistent set of APSC lenses (more than Nikon/Canon ). But still neither Canon , Nikon or Pentax have lenses like the Sigmas or the Tokinas f/2 zooms . It also all depends on format. Availability of HQ APSC primes plus WR, SR makes Pentax being ahead in the APSC (despite its market share). Fuji is on par, but on the MILC and expensive side. IMHO, with f/1.8 zooms and a recent Sony-based sensor, there's not all that sense in going FF, because DR and ISO performance of modern sensors from Sony are so good. You'll notice no differences at base isos between 24 mpx FF and APSC. If I want more blur, it's simple to go down to f1.4 (or I better use a longer FL).
From the switcher point of view, I must well point out what lenses are the reason to switch and what are my expectations from the brand I'm going to switch.

But the FF still going to be better. better 100% crop, much better sharpness for wide angle that strugle on APSC DSLR (not mirrorless), 36, 42, 45 or 50MP too without taxing that much the lense. If a lens is good enough for a 24MP FF is good enough for a 10MP APSC... but may not be goood enough for a 24MP APS by a significant margin...

The small APSC prime for Pentax are for good share of them FF design that would be as small on FF. DA/FA35 DA/FA50. There also the FA31, FA43 and FA77 that show that small FF design are actually possible. And it is not sure you'll get better result with an expensive APSC prime than with a cheap FF prime. The DA21 is not match for FA35 on FF, DA/FA35 is not march to FA50 on FF and so on...

the f/1.8 zoom are heavier, more prome to focus error and offer less interresting ranges. Usually a larger format with narrower max apperture give better results.

[bm75]

better 100% crop

No, it's not. Given the same FOV (not the same FL) 24 mpx on APSC and FF are just 24 mpx so sharpness is just the same, depending on single lens. Otherwise cropping a FF to reach the FOV of the APSC resolves in a much much better sharpness of the APSC (it's physics: you crop FF so you loose mpx and resolution).

36, 42, 45 or 50MP too without taxing that much the lense

N0, 50 px stress the lens a lot. But I understand your point for the higher pixel density of the APSC given the number of the mpx (both FF and APSC)..

If a lens is good enough for a 24MP FF is good enough for a 10MP APSC... but may not be goood enough for a 24MP APS by a significant margin...

THis is where mpx count reach the limit of the lenses... I mean: 36 mpx are demanding and for sure 50 mpx are much more. So this could be a point for FF vs APSC but we're reaching the limit of the pixel density...
For what I know FF Vs APSC difference (talking of modern and Sony-manufactured sensors) is about 1 stop - 1,5 stop so , actually, using a lens that's f/1.8 on APSC you quite reach the equivalent DOF of a lens that's f/2.8 on FF (quite all the professional zooms out there). Exposure obviously doesn't change, but for the same FOV you need a different distance from the subject and/or a different FL.
so this is where the problems come with APSC, depending on your style and photographic genre or professional requirements.

the f/1.8 zoom are heavier, more prome to focus error and offer less interresting ranges.

This is not scientifically proven for AF. Yes, Sigmas (esp. the 18-35) could have problems because 1 - they're not OEM lenses , 2 - they are fast lenses , 3 - they possibly need to be calibrated with the S. dock, sell apart , 4 - I'm not sure any professional would give them the "pro grade certification" thus being them tools for competent enthusiasts (those lenses are not WR, unlike the OEM professional 24-70 and 70-200).
At the end, I'm on your side when we say that "overall" FF could be "better" but with many caveats and considering that: 1- nowadays APSC sensors are just very good and 2- for birding and other tele applications APSC is a valuable choice, 3 - If we had FF from the start, perhaps no one would have chosen the APSC.

[Ian Stuart Forsyth]

No, it's not. Given the same FOV (not the same FL) 24 mpx on APSC and FF are just 24 mpx so sharpness is just the same, depending on single lens. Otherwise cropping a FF to reach the FOV of the APSC resolves in a much much better sharpness of the APSC (it's physics: you crop FF so you loose mpx and resolution).

As the size of the pixel decreases it takes a sharper lens to resolve the same amount of detail per pixel as from a pixel from a larger format that is physics.

[TonyW]

You often hear that modern sensors are at the limit of lenses but I doubt if it is true at least as a generalisation.

Although only one part of the camera system equation, and certainly not one that you would make a purchase decision on, If you need to find out the theoretical resolution of a Bayer sensor it is quite easy to do. But it is important to remember that in the real world that resolution can differ a bit due to things like filters, the array and the bayer interpolation i.e. it will be reduced by? Then add the specific lens on and required apertures, diffraction limited etc etc it becomes a different story but FWIW a couple of calcs.

Formula: Sensor height in pixels / Sensor height in mm /2 = Theoretical resolution lp/mm

Pentax K-3 II 24.35mp APS-C
6016 x 4000 pixels; Sensor Size: 23.5 x 15.6mm
Theoretical Resolution: 128.21 lp/mm

Pentax K1 36.4mp FF
7360 x 4912 pixels; Sensor Size: 35.9 x 24.0mm
Theoretical Resolution: 102.33 lp/mm

[Nicolas06]

No, it's not. Given the same FOV (not the same FL) 24 mpx on APSC and FF are just 24 mpx so sharpness is just the same, depending on single lens. Otherwise cropping a FF to reach the FOV of the APSC resolves in a much much better sharpness of the APSC (it's physics: you crop FF so you loose mpx and resolution).

N0, 50 px stress the lens a lot. But I understand your point for the higher pixel density of the APSC given the number of the mpx (both FF and APSC)..

The FE85 f/1.8 despite being not that big and not that expensive reach 40MP score out of a 42MP body on Sony and does only does 16MP on a 24MP APSC Sony (from DxO Tests).

If you look there no lens mounted on K3 that get past 16MP score and that goes to the sigma 35mm f/1.4, there no Pentax lens tested by DxO that goes past 13MP score.

We all know DxO isn't perfect, but this also match the score you'll find on photozone and all. You'll get much more details on a mere M50 on K1 you got for $40, than a the best 35mm like a sigma 35 Art or an FA31 on K3.

THis is where mpx count reach the limit of the lenses... I mean: 36 mpx are demanding and for sure 50 mpx are much more. So this could be a point for FF vs APSC but we're reaching the limit of the pixel density...

56MP on FF is similar to 24MP on APSC in term of resolving power requirement for the lens.
36MP on FF is similar to 15MP on APSC.

At the end, I'm on your side when we say that "overall" FF could be "better" but with many caveats and considering that: 1- nowadays APSC sensors are just very good and 2- for birding and other tele applications APSC is a valuable choice, 3 - If we had FF from the start, perhaps no one would have chosen the APSC.

I do have only APSC because mostly I can go with a smaller system overall and I started with that. I could buy K1 but overall that's too big and too heavy and the lenses I am interrested in do not exist.

At time I am considering what a discounted A7RII + 24-105 f/4 may provide: f/2.8 APSC equiv bokeh/low light and all + quite interresting range in a single zoom with quality that no APSC zoom will ever match in particular for the wide angles and the possibility to crop to 18MP APSC or 10MP m4/3 if I really need the reach. (so up to 210mm equiv.). If I crop that much on APSC, I start to lack sharpness and get significant noise if I am not at iso 100.

[bm75]

Just checked my Nikon AF D 50 1,4 ranking in Dxomark. Speaking of Sharpness , it takes
9 P- Mpx tested with FF D700 (12 mpx),
15 P-Mpx tested with d3600 and d600 (so, 24 mpx FF and APSC),
16 mpx tested with D800 (36 mpx).
If you see DXO score , it increases from 22 (both apsc and d700 FF)to 32 ( 36 mpx d800).
My sum: the more the mpx count the more the P- Mpx sharpness in dxomark, no matter the format.
Clearly the 50 AF D 1,4 don't match with 36 mpx, but reaches its best sharpness performance at about 24 mpx (sensor resolution).
So yes, the more the resolution, the more the perceived sharpness but that's format- independent. What's dependant from the format is the number of the mpx: nowadays you can't squeeze 36 mpx in APSC....

But yes, the smaller the format, the more is the noise. so cropping from APSC noise is evident, you're right. And you're also right if you say that , perhaps a FF image is "cleaner".

But my convinction still remains the same, if the output is 24 mpx, no matter what format, you'll have quite the same resolution (your frame as FOV divided into 24 millions little squares).

[richard0170]

Theoretically the larger the sensor the better the image quality will be due to a number of factors. Larger cells receive more light, less enlargement required for image viewing be it on a screen or a print so any technique faults are minimised, also any minor dust issues. However, in practical terms other factors will tend to take over. When using telephoto lenses at longer distances air quality will have a greater effect on IQ than the sharpness of the lens or the sensor it's communicating with. Is the photographer holding the camera steady enough for the given shutter speed to produce a perfectly sharp image? Is the DOF great enough for the subject to be sharp enough for the image you want? Is the subject properly in focus? So in practical term I am sure APSC 24mp sensrs are more than good enough for the majority of users. Although FF may be more use for landscape due to a larger selection of wide angle lenses available.
Opinion is divided on whether or not using FF lenses on crop sensor cameras produces sharper pictures or not, in my experience it will depend on the quality of the lens to start with. I have had relatively disappointing results from some of my lenses and spectacular results with others on my K3.
As for the Dxomark scores, I would not believe them. They consistently give Pentax lens/camera scores lower than Nikon ones. Why I do not know. They claim to be scientific, but I suspect a commercial bias. I remember back to the early 80's when camera magazines used to produce lpm charts in lens tests. Nikon, Canon, Olympus, Zeiss, Pentax, Minolta and Tamron were always pretty close with Zeiss just shading it, but not to the point you actually see a difference on your prints. I cant believe lens standards have differed by much since those days. As Pentax users I think we are all very satisfied with the IQ we get from our gear.

[Nicolas06]

I remember back to the early 80's when camera magazines used to produce lpm charts in lens tests. Nikon, Canon, Olympus, Zeiss, Pentax, Minolta and Tamron were always pretty close with Zeiss just shading it, but not to the point you actually see a difference on your prints. I cant believe lens standards have differed by much since those days. As Pentax users I think we are all very satisfied with the IQ we get from our gear.

The difference is that back in time if you wanted a 30x40" print you'd shoot with medium or large format. Now you can shoot in APSC or even m4/3 and get a shot that still look great. You can do that with colors, reliably and at isos higher than iso 25.

Pentax is currently changing its lenses to meet new standard. This is what they say with their new DFA50. So the lens is like 5-10 time heavier and bigger (and more expensive). Sony does it on FE. Sigma does it with the Art line.

For years Pentax was focussed on very interresting compromize for me of small and light with good enough quality and not so great results on charts. The picture you take with theses optics are lovely but they dont win charts and reviews. As a consequence Pentax has lost market share. Now they changed their focus and recognized what the clients want: perfect sharpness for 100% crop and charts. No recent Pentax lens is tested on DxO you only get results for APSC, 24MP at most and from their older, smaller designs not optimized for sharpness but for small size... This show.

[surfar]

If you put a tripod mount on it, it will not help the motor work at all. The ArtTechPro is the only AF adapter for Pentax and per their own website it have quite a few limitations

Youtu.be

Youtu.be

---------- Post added 12-18-17 at 05:35 AM ----------

The DFA150-450 is more than 700g and longer than 50mm

I wonder how long and the weight of the Nikon 400mm f3.5....not sure of the length but weight is 2.8kgs, thats a little different to your 300g Nicholas?

---------- Post added 12-18-17 at 05:38 AM ----------

if my options for using my lenses on Sony are as Nicolas described.

How much does your 150-450 weigh?

[Kunzite]

As much as any other D FA 150-450mm - 2.3kg; it also has a focal range of 150 to 450mm. Why are you asking? Do you think that video is somehow... convincing?

[Rondec]

Just checked my Nikon AF D 50 1,4 ranking in Dxomark. Speaking of Sharpness , it takes
9 P- Mpx tested with FF D700 (12 mpx),
15 P-Mpx tested with d3600 and d600 (so, 24 mpx FF and APSC),
16 mpx tested with D800 (36 mpx).
If you see DXO score , it increases from 22 (both apsc and d700 FF)to 32 ( 36 mpx d800).
My sum: the more the mpx count the more the P- Mpx sharpness in dxomark, no matter the format.
Clearly the 50 AF D 1,4 don't match with 36 mpx, but reaches its best sharpness performance at about 24 mpx (sensor resolution).
So yes, the more the resolution, the more the perceived sharpness but that's format- independent. What's dependant from the format is the number of the mpx: nowadays you can't squeeze 36 mpx in APSC....

But yes, the smaller the format, the more is the noise. so cropping from APSC noise is evident, you're right. And you're also right if you say that , perhaps a FF image is "cleaner".

But my convinction still remains the same, if the output is 24 mpx, no matter what format, you'll have quite the same resolution (your frame as FOV divided into 24 millions little squares).

DXO Mark isn't a great source for lens information. I trust them more for sensor information.

I agree that 24 megapixels is 24 megapixels with regard to resolution. The reality of getting pixel sharp images with 24 megapixel sensors is that it is easier to do so with full frame than with APS-C. The more pixel dense the sensor, the more likely you are to get some softness in your image due to camera shake or diffraction or whatever. All of this depends on the quality of the lens used, shutter speed, and aperture used. Shoot your 50mm f1.4 at f1.4 on a 24 megapixel APS-C camera and you probably aren't going to get pixel level sharpness across the frame. Shoot it at f8 and you probably will (assuming no subject or camera movement).

What I find is that full frame is generally quite a bit better at holding onto dynamic range above base iso and also having less noise and that is where your APS-C image will tend to struggle a bit more.

[surfar]

convincing?

As convincing as Nicholas?