rmorrison1116 Loc: Near Valley Forge, Pennsylvania

All those extra megapixels come at a cost. As an owner of a Canon 5DSr I know of what I speak from personal experience. Sure the resolution and details all those pixels produce is amazing but, as previously mentioned, you give up a lot for it. My D500, D7200 and 5DIV get used way more than my 5DSr because they are faster, create smaller image files and are a whole lot more practical and forgiving them the 50 megapixel camera. If I demand mind boggling detail then I use the 5DSr. A good example; I attended the Philadelphia flower show the other day. Did I use the 5DSr? No, I used my D7200 and 5DIV. The D7200 is much better with the available lighting and it's images are quite nice. If you don't want or need the advantages the fewer pixel cameras offer then get the more expensive one, but remember, you will be giving up useful features, and if you shoot RAW, you may need a faster computer with a lot more storage capacity. Those mega megapixel image files are huge.

Jim Bob

Nice dissertation. I guess the answer to the OP is buried in there somewhere. Thanks.

selmslie Loc: Fernandina Beach, FL, USA

It's not enough that I agreed with you and supported what you said - fleshed it out with some supporting statements.

I suppose that a shorter, sarcastic and insulting comment would have been more to your liking. But how does that help the OP?

What I said was directed towards MikeMc so that he might use common sense with his original question.

Jim Bob

If I needed a comment to be "fleshed out" I would have asked for it. My comment was clear and unambiguous. You just felt the need to be loquacious and to fake pedantry as another poster suggested. Check you later Einstein.

selmslie Loc: Fernandina Beach, FL, USA

I did not do it for your benefit. You are not the OP.

chaman

Exactly. You did it to stroke your ego a bit more.

Jim Bob

Yep. You nailed it.

Dr.Nikon Loc: Honolulu Hawaii

Bill brings common sense into the picture .., yep ... ......,However ...if you examine posts on this forum ... and go to his site...Regis who shoots with a Canon with 50 mega pixel plus ..., shows that there is no equal in clarity and detail to shooting with a high mega pixel camera ...

As stated .., the high mega pixel camera will not be of much use to a photographer who lacks the skills to use it... Regis demonstrates that his superb photographic skills coupled with so far the highest on the market mega pixel camera equals shots that are unequaled on this blog ..., period ..

Any evidence to the contrary would be welcome ...

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Scotty, my 36mp D810 images look a whole lot better than my 6 mp D70S, which looked a whole lot better than my 2.6 mp Sony DSC-F505 images. There is a theme here. The only constant is the photographer. I completely disagree with you on more resolution not necessarily improving image quality. At least from a technical standpoint.

However, you made a huge misrepresentation by stating that more resolution is better for large prints. This is only true if you have viewers that insist on walking up to a 40x60 or larger print, with a loupe in hand, to see the dots that make up the image. That is not normal, but there are many among us who will do that regardless. Human visual acuity diminishes greatly with longer viewing distances, to the point that a 12mp iPhone X image looks amazing on a billboard. Normally I would PM you on something like this -but this is repeated so often that it needed to be corrected in place.

There is some science behind this - this is far from being an individual's opinion. If you haven't stopped by this website, you may want to at this point. It explains everything.

http://www.photokaboom.com/photography/learn/printing/resolution/1_which_resolution_print_size_viewing_distance.htm

BTW, those multiplex theaters featuring Sony 4K projection use 8.8 mp images. But they do look pretty good, don't they?

The main purpose of high MP cameras is to capture incredible detail for viewing up close - like in a high quality magazine, small to medium sized prints, etc. and for cropping when the pictures are taken with sharp lenses. You can crop a lot without having a serious impact on image quality.

Bill_de Loc: US

And Regis almost always shoots with a 2x converter, hand held. I am always in awe of his results.

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Joe Blow

That 24 MP is more than enough unless you plan on cropping a lot and printing big.

So how many MP does it take for a billboard? https://fstoppers.com/originals/how-many-megapixels-do-you-need-print-billboard-220239

selmslie Loc: Fernandina Beach, FL, USA

You don't disagree with me completely or you would not have to qualify that statement.

It's not an absolute improvement in resolution. Pretty soon you reach a point of diminishing returns - your sensor surpasses the resolving power of the lens which then becomes the limiting factor, regardless of the number of pixels.

The same thing happens with cropping. You end up with a lower net resolution and you magnify whatever shortcomings there are in the lens.

And I am not overlooking the question of normal viewing distance. For a high quality magazine you are probably looking at a viewing distance of about 12 inches. Even at 300 dpi that is only going to call for about a 10 MP image. For a high quality monitor you may need only about 4-5 MP and a 24" viewing distance.

So it really comes down to large prints viewed from much less than normal viewing distance. That's where you might need the extra megapixels.

MikeMc

Thanks for all the responses! I've come to expect a full spectrum of opinions on the most contentious topics on this forum, which is fine. I'm very capable of sorting through all the posts and reaching a conclusion for my particular case. I should be capable of understanding the basics of sensors, pixels, and image definition having worked 22 yrs for a Silicon Valley company doing image processing for semiconductor processing where they are now finding defects on 10-20 nanometer geometries on a silicon wafer, granted that managing a high end camera can be pretty complicated!

So a few clarifying points: 1. I just want the best image quality, given that I won't print huge pictures and will mostly view on a HD monitor.
2. Not a lot of difference in total cost of the top two options I'm considering: Sony a7iii and Sony a7Rii (yes that's a ii as I don't see that I need a iii) because there's no discount on the a7iii and I can get a $900 discount on the a7Rii with the 25-105mm G OSS lens, PLUS a $200 or $300 trade in allowance from my old Oly E10. But the trade in deal ends 3/31.
3. I like some of the features of the a7iii, such as touch screen, bigger battery, dual card slots (maybe) and being the latest and greatest. I have one on order for release 4/10. If I get comfortable with 24mp vs 42mp, I'd get the a7iii. If I conclude that I'll be able to see better IQ, I'd get the a7Rii.

Thanks again for the help!

rmorrison1116 Loc: Near Valley Forge, Pennsylvania

It's not up too me to tell someone how to spend their money, only offer useful advice.
The direct answer to the OP's question is no you don't but simply saying no without saying why isn't very useful and would more than likely be dismissed.

rmorrison1116 Loc: Near Valley Forge, Pennsylvania

Regis always posts excellent photographs but skill is only 1/3 of the equation. The other two thirds are equipment and most importantly, location.