Maximum Focal Distance

[Zhaopian]

Hello,

Do lenses, regardless of aperture, cost, range/zoom, etc., have a maximum focal distance? Is excessive pixelation and poor resolution the same concept?

I photographed a surfing contest the other day and I knew I would have to crop in. I shot surfers anywhere from 300 meters to maybe even 600 meters away. With my focal length to 500mm with a RF 100-500mm (using my R5 because of the 45mp sensor), I got what looks like pretty good images, but of course the subject is pretty small in the frame. So, after cropping in really tight, the image was so pixelated, I couldn't use it. Opening up the image another 30 percent did not help either. Probably can only crop in 10-15 percent without the resolution or pixels going crazy.

I also tried denoise and while that helped some, the image was just not good.

So do lenses have a maximum EFFECTIVE focal distance in which the subject must be within or else it cannot be cropped?

Thanks.

[Waddizzle]

Nearly all lenses can focus to infinity.  No digital camera has infinite resolution.  While the image resolution might be 45 MP out of the camera, you don’t retain the same resolution as you zoom in and crop the image.

Revisit the same photos.  Take a look at the pixel resolution.  Zoom in on a surfer.  Export the cropped image to a JPG.  Take a look at the pixel resolution of the end result.   

[johnrmoyer]

A change in density will refract light. At 300 meters over water, there will be many different air densities between subject and camera. The air will act like an out of focus lens and distort the image.

As the ISO increases, so will the visible noise because there is less signal for the same noise. With a smaller number of photons being counted at each photo site on the sensor, the probability that the count will not be what was expected will increase.

A smaller photo site on the R5 will receive fewer photons in the same time than a larger photo site on a R6. To get greater resolution, one will also get greater noise per pixel, even though the noise is the same for the entire image if the sensors are the same size.

These 2 images were made with my EOS R5 of subjects between 300 and 600 meters distant.  The bird that is higher above the water has less noise than the bird at the surface of the water. The distant shore line in the first photo is more than 1 kilometer from the camera.

I processed both photos using Canon DPP software. Noise reduction, increase saturation, DPRAW focus distance adjustment, unsharp mask with radius (fineness) larger than the noise, and digital lens optimizer.

https://www.rsok.com/~jrm/2024Oct22_Salt_Plains/2024oct22_eagle_IMG_2015c.html 

Bald Eagle (Haliaeetus leucocephalus) at sunrise at Salt Plains National Wildlife Refuge in Alfalfa County, Oklahoma, United States on October 22, 2024 ; EF100-400mm f/4.5-5.6L IS II USM +2x III ; 800.0 mm ; 1/400 second ; ISO 500 ; handheld

https://www.rsok.com/~jrm/2024Oct22_Salt_Plains/2024oct22_eagle_IMG_1946c.html

Bald Eagle (Haliaeetus leucocephalus) is catching a fish at sunrise at Salt Plains National Wildlife Refuge in Alfalfa County, Oklahoma, United States on October 22, 2024 ; EF100-400mm f/4.5-5.6L IS II USM +2x III ; 800 mm ; ISO 800 ; 1/400 second ; handheld ; F/11 Frames with captions added using GraphicsMagick free software.

[Zhaopian]

I was also attempting to game the system and squeeze out a little further reach by using APS-C mode and the 1.6 crop. I have, reportedly, done more harm than good. Sounds like I may need to use an upscaling/upsample software. Or get a lens that goes beyond 500mm.