0lf
•
Senior Member
•
Posts: 1,283
Re: G5x Digital teleconverter vs crop
2
Wolfgang Dempke wrote:
Thank you Olf for taking the time to post a response.
Unfortunately I do not understand the details of your first paragraph. I am a retired electrical engineer and this optical stuff is a bit "over my head"
The G11 has a 28-140mm lens in front of a 1/1.7" 10Mpixel sensor.
The G5x has a 24-100mm lens in front of a 1" 20Mpixel sensor. When you crop from 100mm to 140mm, the remaining sensor area is 1/1.4" and 10Mpixel, same pixel count but bigger sensitive area.
So the G5x has no drawbacks compared to G11 in term of maximum focal length.
I think I get your second paragraph, as I also did some "trial and error" tests and noticed that in digital tele converter setting for example at 2x setting, the entire lens range is doubled, at the 24 mm wide angle I get 48 mm, and at the max zoom I get 200. If I understand your comment correctly digital zoom provides a better magnification at the wide angle setting (24mm), same as if I would use the optical zoom only.
Digital zoom only is applied past maximum optical zoom so it is only useful to have more reach for distant targets. It is convenient because it is accessible with the zoom rocker.
Digital teleconverter, has you said, is applied to the entire lens range. It is useful to add more magnification when you don't want to increase the optical zoom. I give the example of macro where the maximum magnification is not obtained with the maximum focal length as the minimum focus distance greatly increase when you zoom.
The digital teleconverter and digital zoom offer the same amount of magnification for the same quality. A picture taken at 100mm + 2x teleconverter will be exactly the same as one taken at 8,4x optical + digital zoom.
The third paragraph goes over my head again, sorry. But if I get this right, I should use optical zoom only and crop in post processing (crop) with Photoshop Elements. I am not shooting RAW, too much work imho. I read that using digital zoom all the way (17 x or ~ 400mm) has a big IQ impact. So, I would like to limit my use to either digital tele converter (2x setting) or digital zoom to a max of 8.4x, (yellow bar) which would be the optical zoom times two. What I don't understand is if the IQ at the 2x tele converter setting is exactly the same as the "2x" going the digital zoom route to 84.x or do those two software tools use a different algorithm, resulting in one of the setting having a better IQ than the other? If so, which provides better IQ
If you have the time, and the patience with me, please elaborate on the third paragraph please.
I advise to use in camera digital zoom or teleconverter mainly if you don't do post processing for convenience. If you do some post processing, crop is more versatile as it allows you to reframe more carefully.
Crop, digital zoom and digital teleconverter all have an impact on quality because you limit the pixel quantity and sensitive area from which the image is displayed.
At 200mm, for example, by cropping in post you stay at 5Mpixel while in camera, the device interpolate the picture to the definition you set (20Mpixel if L is selected), but in full screen, I don't think it makes a dramatic difference.
At 17x, you work with only 1,2Mpixel so the quality will be quite low. IMHO, the results are excellent at 160mm, good at 200mm, and acceptable at 250mm.
Thanks,
Wolfgang
Sony RX1
Fujifilm X70
Canon G7 X II
Apple iPhone 13 mini
selected answer This post was selected as the answer by the original poster.