Loss of IQ Using Full Frame Lens on a Crop Sensor? I've read conflicting info. online. Some say there is a loss in image quality using a ff lenses on a cropped body, others say there...

inbigd

I've read conflicting info. online. Some say there is a loss in image quality using a ff lenses on a cropped body, others say there is no loss of quality. Does anyone know enough about sensors and lenses, and how these work, to scientifically answer this question?

I've got an old eos-1ds and a couple of L lenses for it, 1 being a 70-200 f4 L. Was considering the SL2 as a small walk around / travel camera. I would like the option to use the L lens on it occasionally and get acceptable shots.

Thanks

Rab-Eye Loc: Indiana

I don’t know if you consider this a loss of IQ, but if you put a crop censor lens on a FF body, you are not using all the megapixels available with a FF lens, simply because you are not using the entire censor with the crop censor lens.

mwsilvers Loc: Central New Jersey

Rab-Eye wrote:

I don’t know if you consider this a loss of IQ, but if you put a crop censor lens on a FF body, you are not using all the megapixels available with a FF lens, simply because you are not using the entire censor with the crop censor lens.

You misread the intent of the thread. He's talking about using a full frame lens on a crop sensor not the other way around.

RWR Loc: La Mesa, CA

inbigd wrote:

I've read conflicting info. online. Some say there... (show quote)

Since you’re using only the center of the full frame lens on your crop camera, expect better quality.
Edit: Most lenses are sharper in the center than the edges.

mwsilvers Loc: Central New Jersey

inbigd wrote:

I've read conflicting info. online. Some say there... (show quote)

Your lenses will work just fine on a crop body. I've got a crop sensor Canon 7D Mark II and almost all my lenses are full frame. Because a full frame lens' image circle is larger than a crop sensor, the outer edges of those lenses will not be used. Since in many lenses, there's more distortion and less sharpness towards the edges, you may find you actually get better results using those lenses on a crop camera. Any limitations you run into will be a result of the SL2's lack of features and controls.

robertjerl Loc: Corona, California

As stated the APS-C sensor only uses the center of the image circle thrown by a FF lens. On the vast majority of lenses that is the sharpest part of the image circle. Thus the over all IQ should be a little better since you won't have soft corners and edges.
The major draw back is that FF lenses tend to be bigger, heavier and more expensive.
I use both a FF and an APS-C body and own no crop sensor lenses. I bought a Tamron 10-24 for my crop sensor but my daughter fell in love with the lens-so it became her birthday present. I do get to use it if I want/need something wider than my 14 mm prime.

Kuzano

Agree with those who say better guality w/ FF lens on crop sensor.

However, little gain on your intent. Losing kit weight. You'll still be packing all that lens weight. Also you'll be handling an unbalanced camera to lens ratio.

Unfortunately since Canon has largely blown off the small mirrorless market, why not look for a better solution.

Jakebrake Loc: Broomfield, Colorado

mwsilvers wrote:

Your lenses will work just fine on a crop body. I'... (show quote)

Exactly! The only non full frame lens I own is 18-135 EF-S which pretty much stays on my 80D. All the others are interchangeable between FF and crop sensor with stunning IQ on either body, a 5D MKII or my 7D MKII.

Rab-Eye Loc: Indiana

mwsilvers wrote:

You misread the intent of the thread. He's talking about using a full frame lens on a crop sensor not the other way around.

Oops! You’re correct; my apologies!

rwilson1942 Loc: Houston, TX

RWR wrote:

Since you’re using only the center of the full frame lens on your crop camera, expect better quality.
Edit: Most lenses are sharper in the center than the edges.

mwsilvers Loc: Central New Jersey

Rab-Eye wrote:

Oops! You’re correct; my apologies!

No apologies necessary. I only mentioned it because given your initial misunderstanding you might now want to add your thoughts on what the OP was actually asking.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

inbigd wrote:

I've read conflicting info. online. Some say there... (show quote)

You've watched the Tony Northrup video on this topic, I suspect. It should be dismissed as hogwash. Full frame lenses will provide equal and often better corner to corner performance than APS-C lenses on an APS-C camera.

mwsilvers Loc: Central New Jersey

Gene51 wrote:

You've watched the Tony Northrup video on this topic, I suspect. It should be dismissed as hogwash. Full frame lenses will provide equal and often better corner to corner performance than APS-C lenses on an APS-C camera.

If I recall, I believe Northrop bases his conclusions on DXO numbers which show that full frame lenses get higher sharpness numbers and greater resolution on full frame bodies than on crop bodies. However those numbers on crop bodies are consistent with lenses especially designed for crop, and are often superior to those crop lenses, so I never fully understood his logic. It's been a while though since I've seen his video.

wdross Loc: Castle Rock, Colorado

inbigd wrote:

I've read conflicting info. online. Some say there... (show quote)

There will be a loss that can go from minimal to noticeable depending on how well the FF lense was designed. Usually, the more expensive film and digital lenses will show the least image loss. The image loss comes from the lense design resolving for a certain size siver halide crystal or pixel. Manufactures don't necessarily manufacture lenses for resolving power beyond the format they were made for.

inbigd

Kuzano wrote:

Agree with those who say better guality w/ FF lens on crop sensor.

However, little gain on your intent. Losing kit weight. You'll still be packing all that lens weight. Also you'll be handling an unbalanced camera to lens ratio.

Unfortunately since Canon has largely blown off the small mirrorless market, why not look for a better solution.

I'm considering the SL2 with APS-C lens as a travel camera but want the option to use the bigger lenses on it sometimes. Will still use the EOS-1DS some also.

thanks