Is Rockwell right or am I mad?

Pistnbroke

With a few minutes to waste I tested my Sigma 150-500 on my D7100 and D3200 to prove the loss of LPF made a difference. (allJPEG +9)
I photographed a house number at about 50 yards ..viewed in Microsoft office picture viewer....The image on the D3200 showed more detail.at 100% Crop .??? Then I noticed the D3200 was set for small only 6 MP as I had been using it for ebay photos....strange...6MP was sharper than 24 mp ...
so I tested the D800 D7100 and D3200 at large and small ...
Every time the small 6MP was sharper by looking at the grains of sand in the mortar ( this lens has fine tune zero so good for the D3200)
So come on whats the reason here..diffraction at F8 ?

donaldejose

Could it be a function of the software in camera which takes the 24 mp raw data coming off the sensor and turns it into either large or small JPEG? In other words, the small JPEG generator is just adding more sharpening? Just an idea.

haroldp

Don't mistake acutance for detail.

... H

paulr

Wow Mr H had to look that word up "Acutance".

Pistnbroke

I tried this with the 14mm Samyang on the D800 and the Large was much better than the small so are we saying the Sigma 150-500 can only resolve 6MP so we dont need any more while the Samyang can do 20 MP so we do .........

PB_PM

Rockwell is nuts, you well that's something else. This all comes down to jpeg compression settings, in camera sharpening, picture controls (each gives a different perception of sharpness due to contrast settings), and other baked in factors. That is why I do not shoot jpegs unless requested to provide files right away at an event.

donaldejose

I disagree with always shooting RAW. Nikon's JPEGs are quite good and as long as you have accurate exposure and don't need to recover a significant amount of shadow detail you can let the camera create a JPEG for you as you shoot according to your preferences set in Picture Controls. JPEGs can be post processed a bit, just not as much as a RAW file. But most of the time you should not need the additional shadow recovery RAW gives you.

PB_PM

The reason I shoot RAW is because the picture controls do not do what i want, regardless of settings. My mindset is, the camera is dumb and does not know what I want.

WestEndFoto

Plus in post every image is adjusted differently. Shooting in JPEG applies the same setting everywhere.

haroldp

Wow Mr H had to look that word up "Acutance".

I looked under the 'A's and there it was. I recommend the procedure highly.

Google also works.

Regards ... H

heartyfisher

?? What you all talking about ??
Show Samples please ..

michael66

Here's a fun article.

Introduction to Resolution and Sharpness of digital images and digital cameras

spraynpray

I disagree with always shooting RAW. Nikon's JPEGs are quite good and as long as you have accurate exposure and don't need to recover a significant amount of shadow detail you can let the camera create a JPEG for you as you shoot according to your preferences set in Picture Controls. JPEGs can be post processed a bit, just not as much as a RAW file. But most of the time you should not need the additional shadow recovery RAW gives you.

There is always ADL to recover shadow detail in camera. You can set it to high if you like.

Pistnbroke

All this is fine but we dont seem to be getting to the answer to the original question ..why is 6MP giving me a sharper more pleasant picture than 24 MP on this 500mm lens ? Theres not a lot in it maybe 10%. If photographing birds clearly the feather detail will be better

heartyfisher

All this is fine but we dont seem to be getting to the answer to the original question ..why is 6MP giving me a sharper more pleasant picture than 24 MP on this 500mm lens ? Theres not a lot in it maybe 10%. If photographing birds clearly the feather detail will be better

To its like asking why I am floating when I should be sinking ... You have not provided enough information .. are you in a vat of oil are you in the dead sea are you wearing a rubberducky ..
Please provide sample images .. and settings.

Pistnbroke

Will go find some ducks on the canal ....!!!

heartyfisher

LOL thanks :-)

~:>

snakebunk

The Sigma 150-500 is not very sharp at 500mm. If it can only resolve 6 mp it makes sense that it looks sharper since each pixel is calculated out of the value of four pixels. It would be strange though if you can actually see details in the 6 mp image that is missing from the 24 mp image.

In other words, I think four blury pixels can make one not so blury pixel. If you shoot at F8 and 400mm I think you will get sharper images at 24 mp.

donaldejose

Something is happening which has not yet been explained.

heartyfisher

Something is happening which has not yet been explained.

Something may be happening but is at the moment undefined if it is or is not :-) or what it is in the first place ...

Pistnbroke

Well I found some ducks but being somewhat variable in there movement reverted to a fixed chart ...It transpires that the 6MB images feature much more ringing around black/white transitons than do the 24MP even though the settings have not changed ...so can anyone explain that??..So acutance it is then ...more pleasing to the eye.
Here is a 100% crop from a 6MP at f 11 and sharp +9 ( comming when I work out how to do it ..no attachments it seems the instructions at the top of the forum are gibberish to me)
sorry folks still cannot get an image to display