Panasonic FZ1000 vs GH4 with 14-140mm f/3.5-5.6 (1): 90% of value for 50% of price?

Panasonic GH4 is a fantastic camera: on one hand it is based on long refined concept (4^th generation after all), with operation pretty much unchanged from its predecessor. On the other, it stirred the industry by introducing two breakthrough technologies: DfD (Depth-from-Defocus) AF system and 4K video internally recorded with very good codec. All this at a price point matching prosumer cameras of other manufacturers. In my case it got paired with the new 14-140mm lens, making very flexible and comfortable all-around combo.

However, recently another bomb dropped: FZ1000. With even larger range of focal length of its brighter built-in lens, the same DfD focusing, the same 4K capabilities, similar body shape and only half the asking price it felt as reasonable contender.

Why the contest? Since I’m an amateur photographer, I base my choices on value-for-money, provided image quality is at  acceptable level and there are no disqualifying handling and control issues. All that is obviously subjective, but I’ll be explaining my weighting factors. Anyway, based on paper specs, it looked like FZ1000 can provide 90% of GH4 capabilities at 50% price. I already learnt hard though, that many things can only be verified hands-on. A bit surprisingly, apart from excellent series by Andrew Smallman , I could not find any decent comparison of those two setups. Fate brought a well priced second hand FZ1000 in front of my eyes, and I pulled the plunge…

So there we go, waiting for the postman I start with spec-to-spec comparison, in part two I will verify how those assumptions meet reality.

1.     Body and handling

Both cameras are similarly shaped, with sensible ergonomics based on large hand grip and electronic viewfinder hump.

	FZ1000	GH4
Weight (with battery, card and lens hood)	856 g	844 g
Depth (transport:hood reversed, lens retracted, cap on)	134 mm	136 mm
Depth (hood on – wide angle)	193 mm	173 mm
Depth (hood on – telephoto)	232 mm	218 mm
width	135 mm	130 mm (135 with eyelets)
height	98 mm (103 with hood)	90 mm (93 with hood)

Menu system is based on the same scheme. Adapted for touch control it is very legible, but laborious to scroll through. Customisation capability (especially valid for GH4, competing for the top spot with Olympus E-M1) of the cameras is moderate.

Control layout is very similar too, although there are clear differences in absolute number of buttons (accessibility of main control parameters, direct vs indirect focus point control) based on price point and intended user group. Both cameras feature swivel display of the same proportion and size, but only GH4 offers touch control.

About the only feature FZ1000 gains that GH4 does not have is a zoom lever around shutter button. There is number of nearly equivalent solutions, however differing in implementation (due to construction):

• Dual dial setup of GH4 is replaced with push-dial known from G series. I like the idea, but execution of the latter was always poor, so look forward to see if there was improvement in that department
• Zoom/focus switch on the lens. If implemented properly (variable adjustment speed depending on the mode), it can be more valuable than focus-by-wire of 14-140 and most other MFT lenses
• Leaf shutter: fixed lens and smaller image circle allowed for the quieter and faster solution. Especially the latter is very important when taking photos in bright conditions with fill flash.
• Buffer depth reduced from 40 frames to 10

The most important loss of FZ1000 is lack of buttons to directly adjust major parameters: ISO, exposure compensation, and white balance, present on the top plate of GH4. That forces to use 4-way controller to take over these functions, losing direct focus point selection as a result. Of course that slows down speed of camera operations (that’s one of the reasons for the premium price of GH4), but on the other hand this can make the camera less intimidating for users that only occasionally drift out of Auto mode. The pad itself offers buttons action only, but dial capability of GH4 are pretty much limited to the same due to shape of the rear part of the hand grip. GH4 also offers 1 more position of custom settings on the mode dial.
Crucially though, FZ1000 keeps both focus mode lever with AE/AF lock button as well as drive mode dial.

The difference is the lack of touch control of the swivel screen of FZ1000: even though I am not a big fan of smearing the display, features like soft Fn buttons or other predefined controls, as well as ability to select focus point (especially when button selection is restricted) or to trigger the shutter by pointing the subject in some situations may be valuable. Again, that was the choice Panasonic accountants made to undercut Sony RX10, and something potential buyers need to judge based on their use preferences.

GH4 body is sealed to make it ‘dust and splashproof’, there is no rating for FZ1000.

Functionality for the stills is identical, including focus peaking, zebras, highlight/shadow curve etc.

Functionality for the movies on the other hand differs: the headline UHD 4K is the same (but no Cinema 4K), and all the high bitrate HD modes are axed. Also CinelikeD and CinelikeV curves are present, but gone are all the features that make GH4 so valuable for advanced videography: master pedestal, syncro scan, variable frame rate etc. Oh, and the headphone socket for sound control is gone too. That pretty much defines the audience for the hybrid camera, although lack of lens mount will be the fact putting off many movie makers in the first place. For occasional footage and try out of 4K (or recently added 4K-photo modes) options given should be plenty enough.

2.      Image quality

The main reason for the contest is theoretical very similar image quality. I’ll show some numbers to explain why it makes both setups to be in the same league.
The comparison is based on the assumption (valid for my usual subjects) of identical shutter speed - in that case exposure is defined by combination of aperture and ISO numbers. So GH4 would work with more moderate aperture of 14-140 mm lens, but bigger sensor lets it get away with higher ISO. FZ1000 would loose on quality because of noise produced by its smaller sensor, but makes up by offering brighter lens.

Panasonic GH4 is equipped with 17.3 x 13 mm 4632x3472 (4/3” 16Mpix) sensor, FZ1000 with 13.2 x 8.8 mm 5488 x 3644 (1” 20Mpix).

Comparing colour depth and dynamic range is simple and GH4 wins by about 1 stop each.

Noise quality of the image is a bit more complicated matter though. The obvious conclusion is GH4's twice bigger sensor area have twice bigger light gathering capability, however FZ1000 chip is based on BSI (back side illumination) structure. As a result its low light noise level is reached not at twice the gain (ISO value), but at around ISO800 for GH4 and around ISO500 for FZ1000 (the numbers were averaged with other cameras using the same sensors  - E-M1 if the first case, RX100III and RX10 in the second and rounded  - which is OK for approximation purpose). Assuming linear noise characteristics (valid in pretty wide band of exposure), that can be translated into proportional amount of noise at identical ISO setting. So the first coefficient would be 800/500=1.6

TZ1000 sensel count is bigger: 20Mpix vs 16Mpix, which would yield downsampling advantage of 25% (coefficient of 0.8 when based on GH4). Before I stick to this value, there is one important factor to take into account: sensor format. GH4 aspect ratio is 4:3, TZ1000 is 3:2. Both have pros and cons in general and I’ll come back to them, but at this stage it needs to be addressed, that for fair comparison crops of identical aspect ratios should be analysed, not the total count. So, 4:3 crop of 20Mpix reduces effective number to 17.6 Mpix (only 10% more or 0.9 ratio), but 3:2 crop of 16Mpix drops the number to 14.3Mpix and pulls the ratio down to 0.72. Picking the right value (or average based weighting factors derived from proportion of images taken at specific ratios) seems to be a bit fuzzy, so I will stick to the initial result as simple, round, and being average of the other cases.

At that stage GH4 lead reduced to only 30%, and we have still the last factor to compare: lens brightness. FZ1000 is equipped with lens of aperture ranging from f/2.8 at wide angle to f/4 at narrow. The test setup for GH4 contains lens of aperture ranging from f/3.5 to f/5.6. That means, at wide angle, the sensor of the former will receive proportionally from 56% (2/3 stops, translates to coefficient of 0.64) to 100% (1 stop = 0.5 ratio ) more light. Keeping exposure parameters the same and reducing image brightness proportionally at processing will suppress the noise of TZ1000 (ETTR approach) or it will let reduce gain (and noise) proportionally at the moment of exposure. Thus, especially at the long end, it is now the hybrid leading by up to 30%! That result is more likely to be true in the centre of the image, further away vignetting will play its role. What’s more, achievable depth of field at full aperture will be comparable.

Anyway, combination of excellent sensor together with bright lens might push GH4 with 14-140mm lens out of it leader spot.

There is no simple way to judge image sharpness (resolution and contrast) nor other factors (distortion, aberrations) other than take pictures. Looking forward to the real battle!

Read next:  Panasonic FZ1000 vs GH4 with 14-140mm f/3.5-5.6 (2): ergonomics