Optimum sensor format for wide-angle?

[WS007]

I plan to acquire a camera with wide angle objective, both for photos and video (Lisi, my wife, has an Olympus EPL-6 with the 60 mm macro, no need to purchase another macro setup in the same houshold).

I am confused with the choice of different types of digital cameras and sensor formats that changes from year to year (the hot pots from today beeing the lame ducks of tomorrow). Below several combinations of camera/objective/housing & dome that are within the budget (estimated price in Euro). Depending on housing, MFT, APS-C and VF formats are possible. Is the difference in image quality between different sensor types substantial enough to justify the extra cost of VF (spending >3000 Euro for a setup with moderate image quality is definitly too much - then rather spend a little more)? Are there people out that can compare the different sensor format types based on their own practical experience?

Oly OM-D5II/Pana 7-14mm/Oly: 3200 Euro.
Lumix GX85/Pana 7-14mm/Nauticam: 3500 Euro.
Sony a6500/Sony 10-18mm/Ikelite: 3700 Euro.
Sony A7II/Zeiss 16-35mm/Ikelite: 4800 Euro.

Main emphasis is pure image quality. Besides this, also good image stabilisation and 4K video may play a role (How important are 4K video and 5-axis IS in reality?; so far only the a6500 has both 5-axis stabilisation and 4K).

Wolfgang

 

[Storker]

Sensor format isn't that important for IQ, at least if you look at system cameras of the same sensor generation. For each sensor size step down, you gain about 1EV DOF at the same aperture and lose about 1EV in low-light noise. So, a 24x36mm sensor camera will give about 1EV better S/N ratio than a "crop" sensor camera, which again gives about 1EV better S/N ratio than a m43 sensor camera. OTOH, the DOF varies in the opposite direction, e.g. f/8 on a m43 camera gives about the same DOF as f/11 on a "crop" sensor camera and f/22 on a 24x36mm sensor camera. At the same AOV, of course. So, if you shoot 24x36mm at 1/125, f/22 and ISO1600, you can effectively get the exact same result shooting "crop" sensor at 1/125, f/11 and ISO800, or m43 at 1/125, f/8 and ISO400. Provided that the AOV and glass quality are comparable.

For me, the most important issues determining choice of system are selection of lenses, and user compatibility. I use Nikon topside, both FX and DX sensor depending on specific use, but I chose a m43 system for UW shooting due to the combination of comfortable size and decent selection of lenses.

It's all about glass and ergonomics. At least IMNSHO. And since you already have one m43-based system in house, I'd say that you'd need a pretty good reason for not choosing a m43 camera for WA as well.

 

[Nemrod]

Look at it another way, today's largest sensors will provide equal performance to tomorrow's smallest sensors.

Sometimes I miss good old portable 35mm sensor on a roll.

N

 

[MaxBottomtime]

One of the nicest things about large sensors are that you can crop and save a photo at a reasonable size without losing pixels. I've noticed an improvement in the quality of my photos since going from a Nikon D700 to a D3x. They have similar sized 35mm sensors but the D3x has twice the megapixels. Unfortunately I dive exclusively in dirty water so I haven't had the opportunity to see what the camera can really do.

 

[Storker]

One of the nicest things about large sensors are that you can crop and save a photo at a reasonable size without losing pixels. I've noticed an improvement in the quality of my photos since going from a Nikon D700 to a D3x. They have similar sized 35mm sensors but the D3x has twice the megapixels.

Going from 12 to 24 MPx is of course nice, but both those cameras have an FX sensor, and the D3x has at least a half generation newer sensor than the D700. So sensor size isn't a point here. Pixel size and sensor generation are the issue in your comparison. And if we go to current cameras with today's sensor technology, the DX sensor Nikon D7200 has 24 MPx, and the m43 sensor Panasonic GX8 has 20.

 

[WS007]

Thank you for the input guys!

I found Storker's comparison of sensor types regarding S/N and DOF very useful. For WA images, when environmental ligth has to be used, the difference is not so small, I think...
(I have difficulties in understanding some abbreviations, Storker: what means EV: thermal noise in electrone Volts (eV)?. What OTOH or IMNSHO?)

Concerning further technical development of S/N one must say that todays sensors come already close to the physical limits, i.e. electronic noise at ambient temperature. Only solution is to cool the sensor, what is unpractical for photographic use (we do so with our reserach cameras at the biophysics institute where I am working with, where every photon counts). Or just to increase the size of pixels...

Lets come to optical quality of lenses now:
It seems that also the optical quality of objectives is related to sensor size (Huygen's principle?). When looking at the sharpness (i.e. how many pixels can be resolved optically - termed "perceptual megapixels" by DxO) there is a hughe difference between the lenses I mentioned above: The Sony 10-18mm is worst, providing an optical resolution of at most 6 perceptual MPix, depending on aperture, the Pana 7-14mm performes sligthly better, providing > 10 perceptual Mpix at apertures of 4 and 5.6, at smaller apertures providing only 2 - 6 perceptual Mpix, whereas the Zeiss 16-35mm gives > 10 perceptual Mpix throughout the entire range.
see here: Sony E 10-18mm f/4 on Sony A6000 vs Panasonic Lumix G Vario 7-14mm F4 ASPH on Olympus OM-D E-M5 vs Sony FE Carl Zeiss Vario-Tessar T* 16-35mm F4 ZA OSS on Sony A7R II | DxOMark

=> is there something wrong with the perceptual Mpix concept of DxO, that I missed so far, or is the difference in image sharpness indeed so dramatic in practice?

Wolfgang

 

[Storker]

I have difficulties in understanding some abbreviations, Storker

Sorry

what means EV

EV: Exposure Value. 1EV is opening one f-stop, halving the shutter speed or doubling the ISO.
Also: DOF: Depth Of Field; AOV: Angle Of View

What OTOH or IMNSHO?)

OTOH: On The Other Hand; IMNSHO: In My Not so Humble Opinion.

if you shoot 24x36mm at 1/125, f/22 and ISO1600, you can effectively get the exact same result shooting "crop" sensor at 1/125, f/11 and ISO800, or m43 at 1/125, f/8 and ISO400.

Let me try to make this clearer as well. Let's say you want to shoot at 7mm on a m43 sensor. It'll be very, very difficult - if at all possible - to look at a picture and say if it has been shot on either of these combinations:

• m43, 7mm, 1/125s, f/8, ISO800
• DX (15x21mm) sensor, 10mm, 1/125s, f/11, ISO1600
• FX (24x36mm) sensor, 14mm, 1/125s, f/22, ISO3200

Of course provided that the sensors are of the same generation and have roughly the same number of megapixels.