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-   -   If Sensor Size Doesn't Matter, Why Buy a Bigger One? (https://e-group.uk.net/forum/showthread.php?t=51121)

blu-by-u 2nd August 2019 07:04 AM

If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
Was reading this on the fstoppers.com, I got several questions. Maybe some who have the luxury to own both FF and mft can enlighten.

1) Are not smaller sensors a tat sharper? Evidence in the small handphone sensors against the mft. If so, won't the mft sensors show some difference as compared to the FF?

2) Wide angle, would the 7mm of the mft not look the same as that of a 14mm from a FF?

3) Shallow Depth of Field, Won't it be the same? a 50mm of a mft and that of a 25mm of a FF


if sensor size doesn't matter why buy bigger one

Walti 2nd August 2019 07:37 AM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
Hi Henry

There are differences in performance between the 4/3 and 35mm sensors and systems.

Focal length, as you know there is a crop factor of 2 meaning that a 4/3 lens focal multiplied by 2 gives the equivalent field of view to the 35mm equivelent.

Depth of field, because you are using a shorter focal length to get the same field of view the depth of field also changes and this is easiest thought of as a crop factor too, so an f stop on a 4/3 system will give a depth of field the same as the f stop on a 35mm multiplied by 2, which for sport and wildlife is great, but for portrait work is a problem, so you can now get f0.9 lenses for the 4/3 system to compensate for this. So a photo taken on a 4/3 system at f2.8 gives the same DOF as one taken at f5.6 with a 35mm system

Sharpness, I really don’t know whether the smaller pixels give a sharper image or not, someone else will have to advise!

Low light performance, the performance of the 4/3 system does lag behind the 35mm system for low light but is catching up. That’s all to do with pixel size and the amount of light actually focussed onto the sensor, but it’s a personal choice as to whether the performance is good enough for you! It certainly is for me! Interestingly some of the comparisons of sensor performance put the current 4/3 devices in the same league as 35mm so it’s not going to be long before there’s equivalency between the two systems.

Defraction. The smaller pixels mean that diffraction is a potential issue with the 4/3 system, and I note that Olympus have changed their advice since the recent firmware updates for the OM1ii changing from f8 to f11 as their recommended defraction free f stop!

I think I’ve covered everything, but I’m sure others will chip in!

Walti 2nd August 2019 07:37 AM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
Don't know how that happened - but it's not worth saying twice! ;)

MJ224 2nd August 2019 10:40 AM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
Quote:

Originally Posted by Walti (Post 486714)
Hi Henry

Sharpness, I really don’t know whether the smaller pixels give a sharper image or not, someone else will have to advise!

I have been led to believe that the pixels are about the same density in both FF and MFT sensors...….Unsure actual size tho'

A you tube video if I remember correctly...……..*chr

Walti 2nd August 2019 11:31 AM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
Quote:

Originally Posted by MJ224 (Post 486740)
I have been led to believe that the pixels are about the same density in both FF and MFT sensors...….Unsure actual size tho'

A you tube video if I remember correctly...……..*chr

They can’t be at the same density if you are comparing the same number of pixels, a 20MP 4/3 sensor has to have the pixels more densely packed than a 20MP 35mm sensor.. multiply the number of pixels by the area difference then they’ll be at the same density - a 35mm sensor is roughly 4 times the area of a 4/3 sensor giving 80MP at 35mm for them to be the same.

MJ224 2nd August 2019 11:45 AM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
Yes, I see your logic...……..:confused:

wornish 2nd August 2019 11:59 AM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
If you want to get into the details here is a good explanation.

https://clarkvision.com/articles/doe...l.size.matter/

For most users the difference between a FF and M43 image in typical use is unnoticeable.
It's only when you get to extremes that things may be different.

What is different though is the size and weight of the lenses!

TimP 2nd August 2019 01:16 PM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
Quote:

Originally Posted by wornish (Post 486772)

What is different though is the size and weight of the lenses!

That’s exactly what brought me to m43. Camera is a good bit smaller too. For my needs the pixel count is fine, obviously more is better but it is more than made up for by the size / weight thing.

MikeOxon 2nd August 2019 01:16 PM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
As Wornish has said, the size and weight of lenses is an important factor, especially for tele-lenses.

There are, however, other factors that can enhance smaller lens designs. Most MFT lenses are 'telecentric', which mean that the rear element is as large as the sensor and allows all the light rays to strike the sensor at a perpendicular angle. This feature improves image quality at the edges, especially for wide-angle lenses. Some old lenses for film cameras perform very poorly on digital sensors because the light rays are oblique.

It is also possible to use different construction techniques for smaller lenses. The lenses used in phone cameras often exploit the possibility of using extremely aspherical designs which enables these lenses to provide higher resolution than is feasible for lenses that cover large sensors.

Already, many sensors have sufficient pixels to out-resolve lenses for their format.

There is an article by Zeiss which explains these aspects and shows some designs for phone lenses. Download from:
lenspire.zeiss.com/photo/app/uploads/2018/04/Article-Tessar-2011-EN.pdf

pdk42 2nd August 2019 01:20 PM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
There are really only two differences in theoretical terms:

- Larger sensors give shallower DoF for a given field of view. A 50mm lens on FF gives a similar field of view to 25mm on m43. Point them both at a subject a metre away and set them both at f2.8. The FF shot will give you a DoF of about 6cm, whilst the m43 shot will give you nearer 13cm. To get the same DoF on m43 you'd need an f1.4 lens. (Calculations using a CoC of 0.03mm on FF and 0.015 on m43 - the frame diagonal/1500).

- Larger sensors (given similar technology) yield lower noise. The difference will be about 2 stops (for regular photo use rather than astro where things change). So, you'll get the same noise shooting on FF at ISO 3200 as you would on m43 at ISO 800, all other things equal. Sometimes that won't matter. Other times it will. Depends on what you're shooting, how much you're cropping, what the final output medium is, what the lighting is like (poor lighting will generally make noise worse even when exposed correctly), ...

In practical terms there are other differences of course:

- Smaller sensor systems generally have smaller and lighter lenses for a given field of view and at a similar f-stop. So, the Oly 300mm f4 is way smaller than the Nikon 600mm f4. However, the Nikon 500mm f5.6 is much closer in size and because the noise performance of an FF sensor is two stops better, you could crop the 500mm to the same field of view and still be better off in terms of total noise than m43.

- Smaller sensor cameras are generally smaller and lighter. Although Olympus are doing their best to equalise this with the E-M1x!

- Smaller sensor cameras and their lenses are generally cheaper than larger systems. Not all cameras and not all lenses - but in general.

- Larger sensors often deliver improved dynamic range. You'll probably get an extra stop or two of DR from a modern FF sensor over the best m43 sensor available today.

Naughty Nigel 3rd August 2019 04:11 PM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
Quote:

Originally Posted by blu-by-u (Post 486710)

1) Are not smaller sensors a tat sharper? Evidence in the small handphone sensors against the mft. If so, won't the mft sensors show some difference as compared to the FF?

Not sure about that, but I seem to remember the Four Thirds consortium settled on the format because it was considered the optimum sensor size to match with lenses that would feed light directly into the sensor and not at an angle; thereby minimising diffraction effects and suchlike.

Olympus also made great play of the fact that their lenses were designed and optimised for digital sensors whereas Nikon, Canon et al were using lenses designed for film.

I'm not sure how valid these claims were or whether some of it was marketing bull.

Also, don't forget that mobile phones and compact cameras tend to use a lot of software sharpening and brightening to 'enhance' images for small screens and social media, but these don't stand up to close scrutiny on a 27" monitor.

pdk42 3rd August 2019 04:30 PM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
Quote:

Originally Posted by Naughty Nigel (Post 486865)
Not sure about that, but I seem to remember the Four Thirds consortium settled on the format because it was considered the optimum sensor size to match with lenses that would feed light directly into the sensor and not at an angle; thereby minimising diffraction effects and suchlike.

Olympus also made great play of the fact that their lenses were designed and optimised for digital sensors whereas Nikon, Canon et al were using lenses designed for film.

I'm not sure how valid these claims were or whether some of it was marketing bull.

Mostly marketing bull I reckon! Apart from size (and cost) I don't see why any of those points wouldn't apply to larger sensors.

drmarkf 3rd August 2019 04:45 PM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
Agree with all of that, however...

Quote:

Originally Posted by pdk42 (Post 486782)
- Larger sensors (given similar technology) yield lower noise. The difference will be about 2 stops (for regular photo use rather than astro where things change). So, you'll get the same noise shooting on FF at ISO 3200 as you would on m43 at ISO 800, all other things equal. Sometimes that won't matter. Other times it will. Depends on what you're shooting, how much you're cropping, what the final output medium is, what the lighting is like (poor lighting will generally make noise worse even when exposed correctly), ...

If you are actually after a specific and quite large depth of field, such as for wildlife photography, you often end up stopping down the FF, so you may lose one of those ISO stops right away.

Furthermore, in real life this isn't just about image quality, is it? FF fanboys conveniently ignore everything else, of course *zzz

So, I don't think anyone has yet mentioned the improved IS systems of smaller sensor cameras, allowing handholding of wide angle lenses for ridiculously long exposures, and doing away with tripods/gimbals/monopods for long telephotos, aiding maneuverability.

A friend of mine does a lot of semi-pro low-light concert & stage photography to a very high standard, and currently shoots both a Canon 1DX mkii and an E-M1ii. He's been toying with the idea of switching entirely to Sony and has been testing various combinations of bodies & lenses from the 3 manufacturers, with the conclusion so far that there is still no outright winner. He hasn't yet tried the A7Riv, but everything else available from all 3 manufacturers wins on some swings and loses on other roundabouts.

Naughty Nigel 3rd August 2019 09:58 PM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
I recently had the pleasure (not) of having to provide expert commentary on a series of technical photographs taken using an Apple iPad. It really was not good.

Somebody from the shipyard had decided to document a procedure by photographing it with the iPad, but they had not stood particularly close when doing so. The photographs look OK on my iPad Mini but their quality on a 27" monitor leaves a lot to be desired. Despite the millions of pixels fine detail is nothing more than a mush! This probably comes down to the small size of the sensor although aggressive sharpening and compression and the lens design won't have helped.

Generally in life bigger is better, but as technology improves the 'critical mass' becomes smaller. iPad sized sensors still have a way to go, but for most photographic purposes the Four Thirds sensors and lenses are more than adequate and actually provide many advantages over full frame and medium format sizes.

IPWheatley 4th August 2019 06:37 AM

Re: If Sensor Size Doesn't Matter, Why Buy a Bigger One?
 
As someone who has bucked the trend so to speak, I recently switched from a crop sensor system to a full frame one. I chose this option for a couple of reasons, the main one being, as the majority of my photography is now landscape focused it seemed the obvious way to go to achieve the best image quality possible. I did not make this decision lightly. I was fortunate enough in that my local camera dealer lent me a Canon 5D Mk3 and three Canon L lenses to try for a week and the results convinced me it was the right move for me. There are disadvantages, as have already been mentioned by others here, the main one being the weight factor, but after a recent trip to The Lakes, lugging around two bodies and six lenses with my old system, the difference is negligible. The advantages are, greatly improved battery life, I used to carry six previously, now only two, and image quality, which to me is a noticeable improvement. Regrets? None on my part. One last point. How many of you here edit in 16 bit, not 8. If not why not? Yes it triples you file size but you can always resize for posting etc. It seems foolish to me not to if you want the ultimate in image quality from whatever camera system you choose to use. Interested to hear other members views on this. As always, regards to all, Ian W.


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