[Finntax]

You can add :

So far, the APS-C equivalent to most FF lens are around the same size.

If by equivalent you mean APS-C designed lens on APS-C body delivering the same reach as FF designed lens on FF body at least I'm noticing a "small" difference in size:

[Sandy Hancock]

I distinctly recall people on these forums complaining that the DA*50-135 was a big lens

If I get the 70-200 it will spend more time on my K-3 than the FF, but I'll be keeping its little brother as well.

[Finntax]

I distinctly recall people on these forums complaining that the DA*50-135 was a big lens

If I get the 70-200 it will spend more time on my K-3 than the FF, but I'll be keeping its little brother as well.

My toughts exactly

[DavidSKAF3]

So, until we know the new model's pixel count and density, determining accurate pros and cons is guesswork at best?

[blende8]

no, 36mp has higher resolution than 24mp, period.
you can see that easily on any dxomark comparison.

What are you talking about?

You can calculate this on your own:
K3 , 24 MP: 65.049 P/mm^2
A7r, 46 MP: 41.667 P/mm^2

[aurele]

If by equivalent you mean APS-C designed lens on APS-C body delivering the same reach as FF designed lens on FF body at least I'm noticing a "small" difference in size:

You got me on the zoom lens

I was more thinking about lens like the Sigma 30/1,4 and 35/1,4.
Both are just big and the difference is nor really huge.

But if you look about zoom, i admit they are bigger than what you need on APS-C, because APS-C allow more reach.

[Sandy Hancock]

What are you talking about?

You can calculate this on your own:
K3 , 24 MP: 65.049 P/mm^2
A7r, 46 MP: 41.667 P/mm^2

Pixel density is not what determines resolution. Pixel number does.
If the former were the case the Pentax Q would ROCK.

[Rondec]

if both sensors have the same pixel density than their is NO advantage of the 35mm sensor.

If the FF is 36 Mp as rumoured, it will have a lower pixel density than the K-3, so should offer better high-ISO performance, while delivering higher resolution.

Am I missing something?

If you shoot equivalent photos, they will have similar performance. The only way you get added performance on full frame is if you shoot a faster (equivalent) lens on full frame compared to APS-C. So, for instance, if you shoot a 50-135 f2.8 on APS-C and a 70-200 f4 on a full frame camera, the end result should be pretty similar or, a 55 f1.4 and an 85mm f2. On the other hand, if you use a 70-200 f2.8 on your full frame, you will have the ability to get a little better high iso performance, the same with an 85mm f1.4 . The high iso performance is directly linked to having more narrow depth of field and if you can't deal with that for some reason and have to stop down, then you have to push your iso up and it goes away. The basic reason for the better performance of full frame cameras has to do with the fact that there are faster lenses available for them than for APS-C, particularly in the wide angle range.

I really hate the equivalence discussions, because they don't really relate to how I shoot -- not on any format of camera. For the most part I will be stopping down a lot and trying to maximize depth of field, which is an anathema to most of the posters on this forum

[Sandy Hancock]

I really hate the equivalence discussions

Me too. That's why I was commenting on something else

[Finntax]

I was more thinking about lens like the Sigma 30/1,4 and 35/1,4.
Both are just big and the difference is nor really huge.

Yeah, on primes the difference is somewhat insignificant.

[blende8]

Pixel density is not what determines resolution. Pixel number does.

Not in my understanding.

[mohb]

On all the various threads about full frame has anybody actually said they are not happy with the quality of their photos from APSC?

[jsherman999]

if both sensors have the same pixel density than their is NO advantage of the 35mm sensor.

There most certainly is. Sensor area along with lens' physical aperture determines the total light that goes into the image. Put more light into the image, you get less shot noise which results in better SNR and DR. Pixel density doesn't matter there (as long as neither sensor is packed with so many pixels that read noise becomes a problem.)

We have a great comparison that shows that ^ - D800 vs D7000/K5. Exact same pixel density, same sensor gen, the D800 has over a stop better noise perf at the same FOV and exposure over most of the ISO range (and better DR as you move up from base ISO.)

There are so many places to start with this that I'm at a loss as to what would help most... this might be a good starting point: dpreview takes an official shot at explaining it.

---------- Post added 02-13-15 at 09:41 AM ----------

On all the various threads about full frame has anybody actually said they are not happy with the quality of their photos from APSC?

When I picked up FF in 2010 it wasn't because I wasn't happy with my K20D output, it was because I was happier with D700 output. (and AF.)

(I just really wished I could have D700-level output with Pentax lenses)

[BrianR]

Pixel density is not what determines resolution. Pixel number does.

Not in my understanding.

How much simpler the forum would be if everyone used ***INSERT PHOTOGRAPHY TERM HERE*** to mean the same thing.

[jsherman999]

I distinctly recall people on these forums complaining that the DA*50-135 was a big lens

If I get the 70-200 it will spend more time on my K-3 than the FF, but I'll be keeping its little brother as well.

I think there are going to be a lot of Pentaxians surprised how good that 50-135 2.8 performs on 36MP FF in auto-crop mode.

---------- Post added 02-13-15 at 10:10 AM ----------

How much simpler the forum would be if everyone used ***INSERT PHOTOGRAPHY TERM HERE*** to mean the same thing.

People talk about 'resolution' in two ways. Basically, lp/mm and lp/ph.

lp/ph -> 36MP is more
lp/mm -> 24mp on aps-c is more

In my experience more more lp/ph is what most photogaphers covet and find they can use.

.