Full Frame vs. Crop - Can you compare Apples to Apples? My next post will show a closeup captured 16MP with the same equivalent focal length. I used a 1.5x crop sensor (Fuji X100T...

selmslie Loc: Fernandina Beach, FL, USA

My next post will show a closeup captured 16MP with the same equivalent focal length.

I used a 1.5x crop sensor (Fuji X100T, 23mm fixed lens, full frame equivalent 35mm) and a full frame 16MP Nikon Df and a Tamron 35mm f/1.8 Di VC USD.

Both images were taken from about 30 inches away on a tripod at ISO 200 1/1000 @ f/2.

selmslie Loc: Fernandina Beach, FL, USA

The first difference you can see is that the Fuji image is darker. That's not the sensor's fault. It's because the camera's lens does not pass as much light as the Tamron. The Fuji lens is almost a full stop darker than the Tamron at f/2.

The visible difference in DOF (0.3 feet for the crop sensor and 0.19 feet for full frame) is simply due to the way the math works out.

Other differences are extremely difficult to see, even after you download the images and view them at 100% or more.

Fuji X100T
Fuji X100T...

(Download)

Nikon Df w/35mm Tamron
Nikon Df w/35mm Tamron...

(Download)

Longshadow Loc: Audubon, PA, United States

Shouldn't the camera's exposure system compensate to get the same EV for whatever light is coming through the lens?

Dunno, can you compare Mackintosh to Golden Delicious?

selmslie Loc: Fernandina Beach, FL, USA

Longshadow wrote:

Shouldn't the camera's exposure system compensate to get the same EV for whatever light is coming through the lens?

Dunno, can you compare Mackintosh to Golden Delicious?

Both cameras were set to the same manual exposure and ISO. That's the only way you can tell that the Fuji's lens is darker than the Tamron's.

If both exposures were made using auto exposure or ISO they might have ended up with the same brightness but you would not be able to compare the DOF, etc.

It's not just a coincidence that the two DOF measurements are proportional to the crop factor.

BebuLamar

In my opinion my Df ISO rating is underated. ISO100 is more like 125 in my opinion.

CHG_CANON Loc: the Windy City

Clear demonstration that the grass is always greener when captured with a full-frame sensor.

joer Loc: Colorado/Illinois

F-stops are just ratios and approximates at that. T-stop are a better indication of the light that hits the sensor, assuming everything else is the same.

BebuLamar

selmslie wrote:

Both cameras were set to the same manual exposure and ISO. That's the only way you can tell that the Fuji's lens is darker than the Tamron's.

If both exposures were made using auto exposure or ISO they might have ended up with the same brightness but you would not be able to compare the DOF, etc.

It's not just a coincidence that the two DOF measurements are proportional to the crop factor.

I doubt that the Fuji lens T stop is that much different. More likely the ISO 100 on the 2 cameras are not rated the same. I found the Df is underated and thus with your example I think the Fuji ISO rating is more correct.

joer Loc: Colorado/Illinois

joer wrote:

F-stops are just ratios and approximates at that. T-stop are a better indication of the light that hits the sensor, assuming everything else is the same.

The attached chart shows two 85mm f1.4 lenses. There is 0.3 stops difference in marked f-stops...that is noticeable in an image.

Lens comparisons require knowledge of optical science to be valid...that is why I stopped doing my own.

(Download)

Ysarex Loc: St. Louis

BebuLamar wrote:

I doubt that the Fuji lens T stop is that much different. More likely the ISO 100 on the 2 cameras are not rated the same. I found the Df is underated and thus with your example I think the Fuji ISO rating is more correct.

The two camera brands Nikon and Fuji use different ISO standards. An unfortunate reality of our digital age but a reality nonetheless. Nikon adheres to the REI ISO standard and Fuji adheres to the SOS ISO standard. We can no longer just assume that ISO X is the same for all cameras. We have to test our hardware and understand what our various camera manufacturer's intended.

Below: To remove the variable of different lenses both photos taken with the same lens. (Nikon set to DX format).

SOOC JPEGs. Exposure set manually for both: 1/4 sec. f/4

ISO for both: 200.

Joe

Fuji

(Download)

Nikon
Nikon...

(Download)

BebuLamar

Ysarex wrote:

The two camera brands Nikon and Fuji use different... (show quote)

As I said I suspect the difference is more of the sensor than the lens although I know lenses can have T stop different. And I know I would be happier if my Df render 1/3 stop darker.

Ysarex Loc: St. Louis

BebuLamar wrote:

As I said I suspect the difference is more of the sensor than the lens although I know lenses can have T stop different. And I know I would be happier if my Df render 1/3 stop darker.

It's not the sensors responsible for the difference it's the processing of the final output images.

Joe

BebuLamar

Ysarex wrote:

It's not the sensors responsible for the difference it's the processing of the final output images.

Joe

But it writes the raw file that way not only the JPEG. I would rather have it render a bit darker.

User ID

Is this going somewhere ?

Ysarex Loc: St. Louis

BebuLamar wrote:

But it writes the raw file that way not only the JPEG. I would rather have it render a bit darker.

ISO applies to the camera output JPEG. Raw files are along for the ride and of course are effected by how the camera meters the exposure. Test our hardware and make appropriate allowance to taste. I almost never expose at my camera's meter recommendation.

Joe