Psergel Loc: New Mexico

Hi,

I have a sort of theoretical question that I'll ask using this hypothetical situation. I apologize up front for the excess of verbiage.

I want to take a high quality picture of a more or less flat subject. Say a weathered barn door. A lot of texture but only a very shallow DOF is necessary and there isn't a whole lot of DR.

I'm using a high quality prime lens of x focal length set to it's optimal f stop.

First I use a high quality 20MP crop sensor camera positioned on a very solid tripod so that the barn door fills the sensor. I take my picture.

Without moving the tripod I replace the camera with a high quality 20MP FF and take the picture using the exact same lens and all of the exact same exposure settings.

Which is going to give me the best results, the picture taken on the crop sensor camera where I do not need to crop the image or the picture taken on the FF camera where I need to crop the image down to include only the door?

Bozsik Loc: Orangevale, California

From my experience the full frame sensors will give you better image quality. I use the D600 and D7100 and that would be the results I would get.

Psergel Loc: New Mexico

Thanks for the straightforward answer. It was also what I was hoping to hear.

MT Shooter Loc: Montana

First, you would have to move a lot closer to get the exact same image with the full frame body. Choosing to shoot from the same spot and crop would result in a smaller image file and lower quality image due to the loss of a major portion of the gross image in cropping. At a small print you would likely notice no difference though. When printing a significant enlargement is where you would see the difference. The 20MP crop sensor image would be of higher quality than a 20MP full frame image that has had half its data deleted in cropping. But had you filled the frame of the full frame camera to the same composition as the crop sensor image simply by moving closer, the full frame image would be of noticeable better quality when significantly enlarged for printing.

banjonut Loc: Southern Michigan

Since they would both be 20 mp cameras, I cannot see how the full frame would ever give you a better picture if you had to crop into the photo to give the same view.

paulw Loc: nottinghamshire

why can t you get closer or further away ? fill your frame with the image you want don t understand you needing to crop anything .will you be trespassing?

Bozsik Loc: Orangevale, California

The sensors are a different quality.

cthahn

Take the two pictures, then analyze them. Yoou can answer your own question and learn something.

MonochromeB Loc: Chandler, AZ

'Best result' is a subjective question, and in your hypothetical is up to great interpretation. Are you looking for IQ or resolution? They are NOT the same.

As others have said, without moving the tripod the .6x or .5x (depending on whose body you are shooting) the images will not have the same field of view, so the mages will not be identical.

The APS-C resolve a high resolution because there are 20MP on a smaller area sensor, meaning the pixels are smaller, and assuming your lighting and camera settings are correct 'enough' to favor the lighting you choose the APS-C shot will have better small detail resolution, yet will visibly pixelate 'quicker' under enlargement based on each pixel containing a smaller piece of the total image when compared to the FF.

The FF sensor having the same number of pixels (20MP) on a larger sensor means the pixels are larger and contain a larger portion of the image than the APS-C, hence will normally produce better Image Quality especially when enlarged for print.

I have done this same 'test' and all it did for me was to confirm what I had read about equivalency but had to prove it to myself.

Never since that had I ever thought about it again, after become intimate with my gear, and knowing through practice what each of my crop lenses produce on my crop body and my standard glass produces on my FF.

joer Loc: Colorado/Illinois

An outstanding question. I don't have comparable cameras so my opinion is not based on apples to apples.

I have been using a Canon MkII and a D7100 which are not exactly comparable and the lenses are different although the Canon lens is a "L" zoom and the Nikon is a Sigma prime with 1.4 ext. Both at cropped to roughly the same size. The images are close but different. I prefer the Nikon but that is just my preference.

I posted a snip from DXO comparing a 58MM at f2.

The D600 definitely has the advantage in sharpness but not in other characteristics. Since its image must be cropped to match the D7100 image I believe it would loose out, but it would be close and the difference may not be discernible with the eye.

mwsilvers Loc: Central New Jersey

Agree completely. A heavily cropped FF image will have a lower resolution then the full image from a cropped sensor.

mwsilvers Loc: Central New Jersey

The simple answer would be that a pixel on a FF sensor is better than a pixel on a smaller cropped frame sensor, but its more complicated than that.

SteveR Loc: Michigan

The other thing to consider is that 20mp in a cropped size area will have more resolution that 20mp in an fx sized area. This is why the cropped area in a D7100 has more resolution that the same area in the D800. although I understand that the size of the pixels are different.

Psergel Loc: New Mexico

I guess this was my lame attempt to get a simple answer to a complex question.
This was a hypothetical situation. In real life I would always try to fill the frame with my subject if possible.

The reason I'm looking for the answer at all is that I am agonizing over the purchase of a Canon 6D or 70D (or possibly waiting for the rumored 7D Mark II). I'm using mostly EF lenses and the difference in cost between the two bodies is not that big of a consideration for me. I don't do video so the 6D seems like a "no brainer" but......
the whole "greater reach with a crop sensor" thing has me hung up on a decision.

I like to take all sorts of pictures and I have very mixed success. My landscapes suffer from dynamic range limitations (and my hdr efforts look artificial).
I'd like to do a bit of birds/wildlife but can't afford a really long lens. At this time my biggest is the 70-300L.

I don't want to do a "brand switch" and whatever I buy may be my last camera. I am not a young guy (another reason why I need the reach).

That is the reason for my question.

I currently use a T3i (600D) and get frustrated by the noise I see unless I ETTR which is hard to do in a landscape with very high DR, even using a CPL.

and.......

I just want a newer, bigger, better etc. ....whatever that may be.

FredB Loc: A little below the Mason-Dixon line.

Just get the damn 6D. Keep the T3 and use either/both when the situation calls for it.