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Scottie

Have to Increase ISO X-T1

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I expected that two cameras shooting with the same ISO, Shutter and F/Stop would have similarly exposed images.

 

That would be a keen assumption, given that ISO is a more or less arbitrary concept (especially for brands like Canon or Nikon that are using the REI standard as opposed to the more "objective" SOS standard).

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If you look at ISO measurements on dxomark, most cameras are pretty close to 'standard'. Olympus cheats a little bit. Also evidenced by the fact that nearly other camera is compatible with 3rd party studio light meters.

 

I'm a huge Fuji fan, but more than happy to admit that ISO values on the x-t1 are total rubbish.

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Hello,

Just, very recently started, to move over to the XT1. No serious disappointments except:-

 

I, almost, always shoot in RAW and in Aperture Priority. However, I have been surprised to find that, quite frequently, the shutter speed seems much slower than I expect it to be and have to increase the ISO. I have checked it against my Nikon D3 using approximately same reach of lens and the same aperture and it varies between one and two shutter speeds faster.

Am I comparing chalk with cheese, or, perhaps, mild Cheddar with strong Cheddar?

Are you keeping crop-factor in mind when you set your f-stop between your full-frame Nikon and crop-sensor Fuji?

I see a lot of people who keep field of view in mind when going from full-frame to crop but completely forget about the difference in how aperture settings work differently on a full-frame camera than it does on a crop-sensor.

 

Tony Northrup pretty much nailed it in this video:

https://youtu.be/f5zN6NVx-hY

 

Also, there is a difference in how much light goes from the aperture to the actual lens even if you use two different lenses, even if they have the same focal length and aperture setting.

As explained by Matt Granger here:

https://youtu.be/jI8uAzX0bBw

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[...]

Tony Northrup pretty much nailed it in this video:

https://youtu.be/f5zN6NVx-hY

 

Also, there is a difference in how much light goes from the aperture to the actual lens even if you use two different lenses, even if they have the same focal length and aperture setting.

As explained by Matt Granger here:

https://youtu.be/jI8uAzX0bBw

 

Tony is quite wrong on that video, or at least he is leading ppl into the wrong assumption.

 

What Tony is talking about the Depth of Field differences, which is 100% true and related to the camera sensor. Larger sensor mean larger area and thus a shallower depth of field.

 

But you still do not multiply the F-stop on smaller sensor camera to get a full frame equivalent of F-Stop, that part doesn't make any sense at all. The F-Stop is a measure of a certain amount of light hitting your sensor.

 

What Matt explained is all true but the differences is mostly because lens constructor are allowed up to 0.5 F-Stop value as error margin. Meaning a Nikkor 50mm F1.8, could have a variable F-Stop from F1.8 to F2.3. That's one of the reason why some legacy lenses from the film era has scratching on the barrel marking the actual F-Stops values.

 

So if you are a Protog, and really need to be that precise, you need to test out your gear to be 100% certain of what you are getting on your lenses. And that variation can happen from lenses within the same series manufactured in the same place at the same time.

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Again the ISO sensitivity of the sensor should be a standard but the are some discrepancies between brands and between cameras of the same brand although there shouldn’t be.

 

 

The aperture, is value expressed in f numbers and it is the ratio between the diameter of the pupil ( which we will consider for this purpose, circular, even if it is not, there is a calculus way to make this calculation anyway)  and the exact focal lens of the  lens.

 

So 2.8  of a 100mm lens corresponds to a the same amount of light let through the 50mm lens at 2.8 BUT the pupil will be larger.

 

This is simply explained here and even if you only have a basic knowledge of geometry and arithmetics you one should be having no problems in understanding any of this.

 

https://en.wikipedia.org/wiki/F-number

 

Ultimately one should point the camera at a grey card reflecting 18% of light, make a reading and produce the image of a grey card with a 18% of reflection with any camera and any lens.

 

Each criterium ( shutter speed, real aperture value as opposed to the theoretical one) has tolerances, staying within the norms, of 33% ( 1/3 of a stop).

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The ISO sensitivity is a standard. It is also standardized how to measure it. If the manufacturers would specify which measurement the have choosen the sensitivities of different cameras would be more comparable. However, according to DxO they seem to be not that different in general. Canon seems to be about 1\4 stop below their specification, Nikon about 1\3, Leica 1\2 (Although the X seems to be 1\4 above),the Fuji X100 about 2\3 below, and Olympus 1 stop below. All refers to the difference between the specification of the manufacturer and what DxO have measured. It does not mean that DxO is right and manufacturers are wrong. It just means that the different measurements do not give that different results.

 

Unfortunately DxO have not measured any of the newer Fuji X cameras. But unless the X100 behaves completely different from the newer ones we can assume that the T1, T10, E2, and X100s/t are not much different from the Canons and Nikons, at least we should not expect much more than 1\2 stop difference. So may be Scottie,s observation of more than 1 stop difference is just subjective and therefore not so accurate.

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I like and dislike DxO, they are good if you need raw numbers but then again their scale is a bit weird. On several occasions you have much older dslr that are equally good then recent top dogs while real world clearly prove the contrary.

 

Also they test only the Bayer sensors, hence Fuji not being tested at all. Not even their lenses.

 

This leaves me with a sour after taste when looking at DxO reports. In the end, they are jus that a raw amount of numbers.

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Are you keeping crop-factor in mind when you set your f-stop between your full-frame Nikon and crop-sensor Fuji?

I see a lot of people who ... completely forget about the difference in how aperture settings work differently on a full-frame camera than it does on a crop-sensor.

 

Tony Northrup pretty much nailed it in this video:

https://youtu.be/f5zN6NVx-hY

 

 

 

 

 

 

 

This is totally wrong. "F stop" is a formulaic representation of the diameter of the lens relative to the length in millimeters:

 

F-stop is the focal length divided by the diameter of the lens. 

For example, a 200mm f/4 lens will be 50mm wide: 200mm/50mm = f/4.

 

The rear element of the lens has no idea what is behind it,  a FF sensor, a crop sensor or 35mm film. The lens' physical properties do no change.

 

Tony has confused so many people he should be fined.

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Back in January 2015 I had shown some of my work shot on High ISO using X-T1 mostly in JPEG and even at the highest ISO setting click here

 

Let me tell you what I learned... You'll lose details during high iso because the lens itself didn't have enough resolution power to combat the noise reduction processing. You might have to set turn on LMO option or you need to get the sharpest lens possible, maybe the macro lens or possibly a Zeiss Otus lens... You be the judge, test every lenses and compare it at ISO 6400... you'll find that some has more details than others, all depends on the lens. You will see what I meant. For safe area, I found that ISO 800-1250 should be fine. What is even better if Fujifilm decide to give us a firmware that allows option to disabled Noise Reduction completely.

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Back in January 2015 I had shown some of my work shot on High ISO using X-T1 mostly in JPEG and even at the highest ISO setting click here

 

Let me tell you what I learned... You'll lose details during high iso because the lens itself didn't have enough resolution power to combat the noise reduction processing. You might have to set turn on LMO option or you need to get the sharpest lens possible, maybe the macro lens or possibly a Zeiss Otus lens... You be the judge, test every lenses and compare it at ISO 6400... you'll find that some has more details than others, all depends on the lens. You will see what I meant. For safe area, I found that ISO 800-1250 should be fine. What is even better if Fujifilm decide to give us a firmware that allows option to disabled Noise Reduction completely.

Just use RAW and don't use ACR LOL! No worries about NR and LMO.

Lens has nothing to do with NR. Most lenses have enough sharpness to resolve 5um pixels. At least in the center of the frame.

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Even in the times of analog photography the resolving power of a lens was just as good as the one of the film which tended to be a weaker link that the lens ( in most cases).

 

When I worked for the Dutch Royal library, doing many thing photographic analog and digital, we were doing a lot of microfilms (which contrary to what most people would normally think were shot generally in 35mm and only very rarely in 16mm or but I’ve never do that, microfiches.

 

This is done like that because analog black and white reproduction meets conservation standards better than digital because one can guarantee the negatives, kept in a refrigerated vault, for 500 years ( they have been tested with a simulation obviously since photography doesn’t exist that long!) .

 

This is a problem that digital photography has yet to address.

Raw or Tiff or Jpegs depend from the ability of computers to open a file , we simply don’t know whether in 100, 250, 500,1000 years computers will still be able to open the files we produce now ( but this is another discussion)

 

The first test of any roll that you shot was to test the negative the way it was developed.

 

Developing was tested every day several times a day to see if by developing you weren’t nullifying all your work by producing a negative that wasn’t able to meet the international conservation and reproduction standards byt having a film with inadequate resolving power.

 

Digital photography is not different.

 

Raw is as close as possible to a film that has yet to be developed.

 

As you develop it and at every stage of further additions to anything you do you lose resolution.

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Good morning,  

 

You have to leave the shutter open long enough for light to react on the "darker" regions of the photo/recording area 

maybe dynamic range should be considered at the same time,

if a maximum sensitivity from light to dark is aimed for the brightest part should be near the highest reaction voltage of the sensor whilst at the shadow end differences in light falling onto the sensor should still be distinguished, to my thoughts this may not be achieved if you dramatically under expose the plate as we are not taking advantage of the higher voltage part of the sensor. The shadow end is compressed into a smaller voltage difference.

 

If underexposing consistently was the complete answer the Camera Chip ( taking in JPEG )  internal converter RAW to JPEG would use it,  multiplying the total  plate brightness or stretching the recorded range ( contrast )

 

hard subject!

 

best regards

 

David

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