[UncleVanya]

This was taken at 250mm with my DA* 60-250mm mounted on a Pentax HD 1.4x teleconverter. Here's the camera data reported by SmugMug via the EXIF data. Note how the focal length was reported. The shot was also cropped in post processing.

CAMERA INFO
Camera RICOH IMAGING COMPANY, LTD. PENTAX K-3 Mark III
Lens smc PENTAX-DA* 60-250mm F4 [IF] SDM
Focal Length 350.0 mm (541.0 mm in 35mm)
Aperture f/13
Exposure Time 0.001s (1/1000)
ISO 2000
Copyright Keith Koether
Date Taken 2022-09-04 13:37:27
Author Keith Koether
City Wheeling
State West Virginia
Country United States
Country Code US
Date Modified 2022-09-11 01:40:33
Flash Off, Did not fire
Metering Multi-segment
Exposure Program Not Defined
Exposure Mode Auto
White Balance Manual
Contrast High
Saturation Normal
Sharpness Hard
Subject Range Distant
Sensing Method One-chip color area
Color Space Uncalibrated
Latitude 40.06762
Longitude -80.72520
Altitude Reference Above Sea Level
Altitude 189 m Above Sea Level
Scene Capture Type Standard
Circle Of Confusion 0.019 mm
Field Of View 3.8 deg
Hyperfocal Distance 484.77 m
Normalized Light Value 13
Software Adobe Photoshop Lightroom Classic 11.5 (Windows)
Name _IMG7898.jpg
File Size 2.10 MB
Size 1920 x 1080

541/350 = 1.54 and a few more insignificant digits. That makes perfect sense.

[nixxo2002]

541/350 = 1.54 and a few more insignificant digits. That makes perfect sense.

x1.54 very accurate

[Larrymc]

Nice image, I really like the isolation! No matter what the crop factor is. This was on a tripod I assume?

[nixxo2002]

Nice image, I really like the isolation! No matter what the crop factor is. This was on a tripod I assume?

Thanks , image was taken handhold

[mlag]

I have never seen that cropping in post processing by x % was expressed by an equivalent focal length.
But I understand that 1.3x crop is an image capture mode of the K3III. So they took the same reasoning as if the K-3III was supporting a MF43 or 1 inch sensor format.... and put the equivalent fullframe 900mm focal length in the exif.


I can understand that the K1 does this to become compatible with DA lenses (APSc mode). Makes sense to me.
Bit odd here on an APSC model, unless we should support in future Qlenses or MF43 or ...

So here it is used as digital zoom. Or equivalent doing cropping in postprocessing.
One could ask why specific 1.3 and not other digital zoom ratio's, if you start going that path anyhow. (I have a Panasonic that goes from 400mm FFeq to 800mm FFeq and as such displays it).


What is the resulting pixel size of the original crop image (the publishing on forum alwas reduces size, so not visible....)?

16 Mpixel-ish ?

[normhead]

While it's fun to speculate on cropping, the goal should be to use every pixel available. Be careful not to lose site. I often go with the 1.4, the F1.7x AF adapter and 300 2.8 so I have choice of 3 focal lengths, and I could probably even stack the TCs. My guess, though I've never tested it, is there would be more resolution at 24 MP with a couple TCs, than cropping the same image, as long as you have high quality TCs, and both the Pentax ones are good quality. Between longer lenses, TCs and cropping, cropping would be the least favourable option. What really counts is the number of pixels on the subject.

With a given lens, the K-3 will give you more pixels on the subject, unless you can fill the frame with the K-1. So my MO would be start with the K-1, K-1 with 1.4 TC, K-1 with F 1.7x if I still need to crop switch to the K-3 as last resort, crop the image. But on action shots, birds and wildlife I start with the K-3 if I have a chocie. The extra FPS can be critical, as well as more pixels on the subject with the same lens and distance.