FF v Crop - low light clarifcation question

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Currently trying to decide between upgrading from my D5100 to D7200 or D610. I mainly take candids of my kids indoors, aside from the extra physical controls, the D7200 will give me better AF performance in poor light versus the extra light gathering capability of the D610 (D750 is not in budget). I have a question though, at the same DoF, does the D610 give better low light performance? For example D7200 at f1.8/ISO6400/ 1/100 v f2.8/ISO6400/ 1/100?
 
The FF is about a stop shallower DoF.
I don't know about Nikon, but with Canon there's significantly more than a stop improvement in high ISO performance between a 6d and a 70d.
 
Like for like, a FF will normally provide a cleaner file. It will be in this case but the difference will be less noticeable for high MP full-frame bodies like the 8xx series for example. Don't forget also, that the noise that you see will not be very pronounced after downsizing for web/email use. As for printing, unless it's quite large i.e. A3+, noise is also not very noticeable if the image has been properly exposed. Truth is, the effect of noise is at its worst when viewed at 100% on a high-resolution screen, at full size. For most applications, this should not be a hindrance.

Hope this makes sense.
 
Like for like, a FF will normally provide a cleaner file. It will be in this case but the difference will be less noticeable for high MP full-frame bodies like the 8xx series for example. Don't forget also, that the noise that you see will not be very pronounced after downsizing for web/email use. As for printing, unless it's quite large i.e. A3+, noise is also not very noticeable if the image has been properly exposed. Truth is, the effect of noise is at its worst when viewed at 100% on a high-resolution screen, at full size. For most applications, this should not be a hindrance.

Hope this makes sense.

Thanks, yes it does. I shoot my D5100 at ISO6400 all the time, it's fine for small print sizes, at 100% you can see lots of noise, but not at normal viewing size. I'm veering towards sticking with DX, cheaper body, can keep my 2.8 zoom and 1.8 on DX is already too thin DoF for me.
 
This is often a problem with FF, you get better high ISO but then you have to stop down to get enough DoF which means you need to boost the ISO (for a given shutter speed) which kind of negates the benefit...

Your example is wrong though as the exposure values have changed - f/1.8 1/100 ISO6400 and f/2.8 1/100 ISO6400 are not the same - the second set is a 1 1/3 stops darker.
 
This is often a problem with FF, you get better high ISO but then you have to stop down to get enough DoF which means you need to boost the ISO (for a given shutter speed) which kind of negates the benefit...

Your example is wrong though as the exposure values have changed - f/1.8 1/100 ISO6400 and f/2.8 1/100 ISO6400 are not the same - the second set is a 1 1/3 stops darker.

Ok, thanks, so in the example above not only do I need to stop the aperture down on FF, I would need to boost the ISO to 12,800 ( or halve the shutter speed) for a like- for- like comparison? On Nikon, it appears that there's a stop difference in noise performance i.e. no difference for equivalent dof/ exposure, which would mean the main benefit for candids/ portraits is thinner dof ( which I don't need)?
 
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Ok, thanks, so in the example above not only do I need to stop the aperture down on FF, I would need to boost the ISO to 12,800 ( or halve the shutter speed) for a like- for- like comparison? On Nikon, it appears that there's a stop difference in noise performance i.e. no difference for equivalent dof/ exposure, which would mean the main benefit for candids/ portraits is thinner dof ( which I don't need)?

On paper, yes although in practice you will find the full frame shot has much better texture detail and is generally nicer - I mean when do you really ever need ISO 12800?

That said, I haven't used my D610 since getting some M4/3 kit as frankly that's good enough at everything and typically I want more DOF rather than less so a stabilised f/1.4 prime gives me great light gathering power and enough DoF.
 
This is often a problem with FF, you get better high ISO but then you have to stop down to get enough DoF which means you need to boost the ISO (for a given shutter speed) which kind of negates the benefit...

Your example is wrong though as the exposure values have changed - f/1.8 1/100 ISO6400 and f/2.8 1/100 ISO6400 are not the same - the second set is a 1 1/3 stops darker.
Not at all. I shoot with wide apertures all the time without having to stop down! That's because I want to shoot at wide apertures?

The DOF of the focused subject doesn't change, you only get a wider field of view with FF.

And when you need to use narrow apertures and raise the ISO, on FF that doesn't really matter as it still doesn't affect the image.

Even when you do up the ISO, you still get a better images as the ISO increases don't affect the IQ as much as when you increase it with a smaller sensor.
 
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For the same filed of view the depth of field will be larger with a smaller sensor - if you have a group of people standing in an arc or not quite together then shooting at a smaller aperture would be preferable if you want to get them all in focus.

Depends on your requirements but there are pros and cons each way.
 
Not at all. I shoot with wide apertures all the time without having to stop down! That's because I want to shoot at wide apertures?

The DOF of the focused subject doesn't change, you only get a wider field of view with FF.

And when you need to use narrow apertures and raise the ISO, on FF that doesn't really matter as it still doesn't affect the image.

Even when you do up the ISO, you still get a better images as the ISO increases don't affect the IQ as much as when you increase it with a smaller sensor.

I feel like saying "Yeah but no but..."

-If you shoot at wide apertures you get less depth of field but the question is will you notice? I suppose it depends on how big the image is and how you view it.

-You only get a wider field of view with 35mm FF if you use the same lens but if you factor in the "crop factor" you can have the same FoV with a smaller format and a different lens... for eg. 35mm format and 50mm = 30/35mm APS-C (x1.5 or 1.6) = 25mm MFT (x2) etc... and with these smaller formats the crop factor works pretty well enough for depth of field too so FF and 50mm at f2.8 would need 30/35mm f1.8 APS-C or 25mm at f1.4 for MFT.

- Of course upping the ISO can affect the image quality but this is camera dependant and also depends on how far you up the ISO and if you'll notice or not.

Currently trying to decide between...

I think you'll need examples from both cameras to be sure of the answer :D
 
your probably best to go full frame, for the most part there isnt m4/3 and aps-c lenses that bridge the speed gap, some get part way, and some are damned expensive/heavy

but if you will always or most of the time shoot slightly stopped down then aps-c or m4/3 will reduce in the gap.

i think the sigma 18-35 1.8 and tamron 60mm f2 (theres a nikon 60mm something too) do bridge some of the aspc ff equiliency gap

the sigma is also better than the nikon primes in that range according to the camera store youtube face off :O
 
Good article on 'equivalence' between formats here http://www.dpreview.com/articles/2666934640/what-is-equivalence-and-why-should-i-care What that article doesn't touch on is the improvement in sharpness that you get with bigger formats (because the lens only needs to deliver lower resolution, therefore image contrast goes up and the picture is sharper [basic lens MTF theory]).

The other thing is noise is a bit of a moveable feast. Bigger formats always perform better in theory, because they collect more light/photons over a larger area, but how the sensor handles that is subject to technological development.

But if you want a shorthand answer, bigger is always better for image quality, all things being equal. Better sharpness, less noise, greater dynamic range. DoF changes too of course, and if that is equalised (by raising both f/number and ISO roughly one stop, on FF vs APS-C) then the larger format's advantage in noise and dynamic range is also neutralised, but the benefit in lens sharpness remains and that's the thing most folks are wanting.
 
But if you want a shorthand answer, bigger is always better for image quality, all things being equal. Better sharpness, less noise, greater dynamic range. DoF changes too of course, and if that is equalised (by raising both f/number and ISO roughly one stop, on FF vs APS-C) then the larger format's advantage in noise and dynamic range is also neutralised, but the benefit in lens sharpness remains and that's the thing most folks are wanting.

Maybe it's more psychological than actual????

The reason I say this is because I seemed to adapt quite well when moving from 35mm film to an APS-C DSLR but when moving from APS-C to FF DSLR after 8 or 9 years with APS-C I struggled a bit and had to keep reducing the aperture to get adequate depth of field and then uping the ISO to get an adequate shutter speed and this went against the grain a bit because for years I'd had the idea that keeping the ISO lowish is bestish :D

I haven't done any deep side by side analysis but my general feeing is that "FF" is better but if you equalise the DoF there isn't a fantastic earth shattering amount in it.

Personally I'm not sure that any sharpness difference matter to me as most of my pictures are now viewed on screen or if in print in smallish prints.

I think that the dynamic range advantage is more useful to me.
 
Maybe it's more psychological than actual????

The reason I say this is because I seemed to adapt quite well when moving from 35mm film to an APS-C DSLR but when moving from APS-C to FF DSLR after 8 or 9 years with APS-C I struggled a bit and had to keep reducing the aperture to get adequate depth of field and then uping the ISO to get an adequate shutter speed and this went against the grain a bit because for years I'd had the idea that keeping the ISO lowish is bestish :D

I haven't done any deep side by side analysis but my general feeing is that "FF" is better but if you equalise the DoF there isn't a fantastic earth shattering amount in it.

Personally I'm not sure that any sharpness difference matter to me as most of my pictures are now viewed on screen or if in print in smallish prints.

I think that the dynamic range advantage is more useful to me.
But weren't you using a 5d mk1?

I always found the 5d mk1 to be underwhelming for some reason, and very disappointing at higher ISOs (which is what I wanted it for!).
 
I had 20D and 5D and now have A7 and MFT but which of my points are camera specific?

5D only goes to ISO 3200.
 
Only the ISO points, which is why I didn't like the 5d.

It's not how high the ISO went, I found that above 800 the IQ was disappointing.

I took me ages to try the mk2 after that and I was pretty impressed by the improvement.
 
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Maybe it's more psychological than actual????

The reason I say this is because I seemed to adapt quite well when moving from 35mm film to an APS-C DSLR but when moving from APS-C to FF DSLR after 8 or 9 years with APS-C I struggled a bit and had to keep reducing the aperture to get adequate depth of field and then uping the ISO to get an adequate shutter speed and this went against the grain a bit because for years I'd had the idea that keeping the ISO lowish is bestish :D

I haven't done any deep side by side analysis but my general feeing is that "FF" is better but if you equalise the DoF there isn't a fantastic earth shattering amount in it.

Personally I'm not sure that any sharpness difference matter to me as most of my pictures are now viewed on screen or if in print in smallish prints.

I think that the dynamic range advantage is more useful to me.

It's not psychological, the differences are there and clear to see, if you go looking for them - though sometimes you have to look quite closely ;) But as standards rise, questions like 'does it matter' and 'good enough for most purposes' certainly become more relevant.
 
Well even to this day there are some who maybe mistakenly like the look the 5D gives better than that of later models.

I found the 5D image quality to be very good and if I looked closely enough I did see an improvement over my 20D and at higher ISO's the 5D pulled clear and I can say the same for my current A7 and Panny GX7 but when the depth of field is equalised I personally don't see an earth shattering difference, and to qualify... not in whole images viewed normally on screen or in prints up to A4-ish which is the largest I've printed for ages.

YMMV.
 
It's not psychological, the differences are there and clear to see, if you go looking for them - though sometimes you have to look quite closely ;) But as standards rise, questions like 'does it matter' and 'good enough for most purposes' certainly become more relevant.

I've no doubt that all of this is true but... I sometimes do try to get out of obsessive geek mode and look at my pictures how others do and when I do that most of the time there isn't a smack me in the face difference once DoF is equalised or there abouts.

As I said, for me FF is capable of ultimately better image quality and I'd not argue otherwise but when fighting for a bit more DoF the difference is IMVHO far less clear cut, assuming I can get over my psychological reluctance to stop the lens down and up the ISO.

If we're looking at 1 to 1 and 1/2 stop difference then maybe that's significant for some but for me there is no clear unequivocal answer and for me dynamic range is maybe more of a worry but that may be because of the gear I have.

Don't know why I bothered posting really :D apart from wanting to add that for me and maybe others too there's not a lot in it if the DoF is equalised.
 
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