tomad Loc: North Carolina

If a full frame sensor is 2.7 times the size of a "so called" 1" sensor does it follow that if the glass and sensor are of equal quality that a 300mm lens on a full frame would be equal to an 810mm lens on a 1" sensor camera as far as the ability to crop to the same quality image?

CHG_CANON Loc: the Windy City

The issue is not the physical size of the sensor nor the full-frame crop factor nor the focal length of the lens. None of these. N O N E.

Your image file has a pixel resolution.
Your image file has a pixel resolution.
Your image file has a pixel resolution.

That pixel resolution - literally the total count of the pixels or the product of the length x width of the sensor in pixels, that - P I X E L - R E S O L U T I O N - is the only issue on how much, or how little, you can crop the image. These are pixel-based digital images after all.

If your 1-inch sensor is 24MP, say in a 3:2 aspect, you'll get images that are sized 6000x4000-pixels, the same 24MP as a DX-style camera (1.5 crop) or the same as a 24MP full-frame sensor. If you want to crop the 6000-pixel "side" to an image that retains just 3000-pixels on the wide side, there is ZERO difference in how you'd edit the image files from any of these 24MP cameras.

Z E R O - D I F F E R E N C E

CPR Loc: Nature Coast of Florida

Nicely explained.
db

charles tabb Loc: Richmond VA.

I think that I understand what you are saying.
Now, I have a Sony RX10IV with a 1" sensor with 20.1 MP.
I also have a Sony a99II with a full frame sensor with 41.4 MP.

Can you tell me how they compare as far as cropping photos?

I just can't wrap my brain around this.

I have really enjoyed the a99II.
But, I just took my RX10IV on a vacation to the Carribbean for 2 weeks and love what it did for me.

fetzler Loc: North West PA

CHG_CANON is 100% correct.

Sensor size can affect noise. Smaller pixels produce greater noise than larger pixels. This is particularly noticeable at HIGH ISO settings. In general, newer sensors are better than older sensors. There are several post processing programs that are great for reducing noise (e.g. DXO), however. In camera processing and post processing have improved with time.

The quality of your lenses also affects the final image. Chromatic aberation can be a problem with cheap lenses but post processing can often but not always clean up this is issue. The resolving power of your lens is very important.
The resolving power of your lens can limit the ability to crop.

It should be noted that lenses for smaller format cameras are cheaper as less material is needed and lens design is a bit easier. There are many Panasonic and Olympus for micro 4/3 that are much cheaper than their full frame equivalents even though quality is high for both formats.

Keeping the above in mind, cheap point and shoot cameras are not as good as the more professional cameras but may still be quite adequate for your needs. For the most part, the photographer determines the quality of the photograph and not the camera.

tomad Loc: North Carolina

Good explanation, thanks!

I'll get more specific about why I asked. I have a Sony RX10 IV with a 600mm lens and my wife has the Sony A7 III with a 350mm lens. I was wondering, for distant wildlife shots, is the length of the RX10 lens going to provide a better quality (uncropped) shot or would the A7 III cropped to provide the same image be better. It seems there are too many other variables to make this a mathematic comparison. I guess I need to set up both cameras to make the same test shot and compare the results after cropping the A7 III image.

PHRubin Loc: Nashville TN USA

The a99 has just over twice the number of pixels as the RX10.
The RX10 has a "crop factor" of 2.7
That means the RX10 will have 2.7/2 or about 35% more pixels on a given subject in the photo.
The Sony will show much more of the scene.

CHG_CANON Loc: the Windy City

In the older days, the cropped-sensor would perform worse. But, that isn't necessarily true today, July 25, 2022, especially when comparing relatively new and relatively high(er)-end equipment. Personally, 350mm on a 24MP full-frame sensor is not a good set-up for 'distant wildlife shots'. But, of course, we'd need actual images to judge what is 'distant' when using a 350mm full-frame focal length.

Usage / shooting technique will likely have more impact on the 1:1 comparison of results vs all other factors. Is the ISO held as low as possible for the situation? Is the image as sharply focused as possible to maximize the details that can be cropped from the images from either camera sensor? Is the post-processing based on industry best-practices, including capturing in RAW?

PHRubin Loc: Nashville TN USA

The RX10 has a 220 mm lens which is 600 mm (35 equivalent) due to the crop factor. The A7 is a 24 MP camera, or it has 20% more pixels. But the Sony puts (600/350)/1.2 or 43% more pixels on an object.

But there is more to quality than only pixel count, noise being a significant factor. The a7 will have much less noise, but if the ISO can be kept low, it should not be that noticeable. Also, lens defects and hand motions are also magnified more on the RX10.

User ID

As best I can ungarble your question, you are using arithmetic instead of common sense, and in the process youre operating the math backwards.

Jrhoffman75 Loc: Conway, New Hampshire

Mr. Rubin is correct. There are two factors at play here. A 300mm lens on a camera with a 1 inch sensor would produce an angle of view equivalent to a 450mm lens on a full frame (1.5 inch) sensor camera. So, to produce an equivalent looking image the full frame camera image would need to be cropped, reducing the pixel count of the final image. That is the primary reason why crop sensor cameras Ike the Canon 7D Mark II are popular with wildlife photographers.

For general photography this effect is mitigated by the design of lenses designed specifically for crop sensor cameras. The 1.6 factor crop-sensor specific Canon wide angle zoom is 10-18mm. The full frame wide angle zoom is 16-35mm.

CHG_CANON Loc: the Windy City

It almost reads like you're saying the focal length of the EF-S / DX lenses are not as published? The EF-S 10-18mm lens is a focal length of 10-18mm. The lens does not have a crop factor. If it could be mounted to a full-frame camera, it would be obvious the lens is a 10-18mm zoom.

When you say the lens is designed for a cropped-sensor body, yes, correct. That 'design' is that the lens is built to sit closer to the smaller sensor and throws a smaller circle of light that just covers the smaller-sized sensor. But still, the lens focal length is 10-18mm. The 'crop factor' is an aspect of the sensor as compared to a full-frame of 35mm film. The crop-factor is not an aspect of the lens.

Jrhoffman75 Loc: Conway, New Hampshire

I clearly stated angle of view. If the same focal length lens is placed on a full frame camera and a crop sensor camera then the full frame image will need to be cropped to have the images look the same. If both cameras have the same number of pixels then the cropped full frame image will have fewer pixels.

olemikey Loc: 6 mile creek, Spacecoast Florida

If you have both available, do a "side by side" comparison, you will see the answer.

jeep_daddy Loc: Prescott AZ