Panasonic TZ70 (ZS50) Review Part 1 Image Quality and Performance

TZ70 Focal Length E135mm. The TZ70 works well for close ups on the run.  I often set Burst Mode for hand held closeups when both the camera and subject are moving. One of the frames is often sharper than the others.

Panasonic has been  a player in the ‘travel zoom’/ ‘superzoom’ category for many years with several current offerings.

The FZ70, FZ200 and FZ1000 each have a DSLR-like appearance.

The TZ70 is completely different in shape, size and style being much smaller, scarcely larger than a standard 3x zoom compact.

Panasonic has managed to fit a 30x zoom into a camera only 32mm deep, utilising a triple extension inner barrel system. This seems to me like a remarkable feat of optical and mechanical engineering.

Compact size and light weight are the key features which define the TZ70, making it very convenient to carry in a small pouch or largish pocket.  By the way,  I never recommend that anybody actually carry a camera  in a pocket, a place almost guaranteed to hold dirt, lint and other bits of stuff likely to get inside and damage a camera.  In a drawstring pouch in a pocket maybe.

I carry the TZ70 in an old Lowe Pro D Res 20 AW pouch which is a little larger than needed but does allow the camera to go in and out easily. 

But compact size and low mass are not advantages when one is trying to make pictures at the long end of the zoom. The TZ70 is not as easy to hold steady as larger, heavier models with a full handle.

The TZ70 is well specified with most of the features expected of a modern electronic camera, including a built in EVF, Mode Dial with PASM , Custom, Scene and Panorama Modes, [iA] Mode for snapshooters and a decent set of controls and functions for the enthusiast including RAW capture and Wi-Fi.

Unfortunately the [Photo Style] feature (which allows users to adjust JPG contrast/saturation/noise reduction/color) which appears on many Panasonic cameras is inexplicably and to my mind, inexcusably missing from the TZ70.

This omission seems to me like one of those “what on earth were they thinking” mistakes. It’s just software after all and its absence will alienate enthusiast users while doing nothing for the snapshooters.

Battery charging is via USB connection with the battery in the camera. Some people like this, others hate it. I prefer to use a separate charger so I can continue to use the camera while the spare battery is charging.  I bought an inexpensive aftermarket charger for this purpose.

Focal length E720mm  RAW capture. This is typical for hand held pictures at the long end of the zoom. Tripod mounting improves sharpness.

Image Quality

The TZ70 uses the very small 6.17 x 4.55 mm (diagonal 7.66mm) sensor with 12 Mpx.

This sensor size is at once the main advantage and disadvantage for imaging capability of  the TZ70 and other cameras which use the 7.66mm sensor.

The advantage is that the small sensor allows designers to fit a very long zoom, this being the raison d’etre of the superzoom type.

The disadvantage is that the small sensor produces considerable luminance noise which impairs image quality.

Exposure  is generally excellent with no problems noted.

Dynamic Range (Highlight and shadow detail) is quite good for a small sensor camera with a slight tendency to blow out highlights when subject brightness range is high.

Colorsare generally accurate in RAW files but JPGs show boosted colors especially greens.

Luminance noise  is present at base ISO, becoming increasingly obvious as ISO rises. Image quality is impaired in RAW or JPG files by ISO 400 with loss of detail.

This is a problem indoors at any focal length and outdoors at the long end of the zoom, as a higher than base level ISO setting may be required.

Chroma noise  appears not to be a problem in the TZ70 and indeed most cameras I have tested in the last two years.

Focal length E720mm from RAW capture

The Lens  delivers variable results changing with focal length. 

At the wide end, center resolution is good but the edges and corners are a little soft.  This might be a problem for landscapes but is of less concern for other types of photo.

In the near wide to mid range of the zoom, the lens delivers very good resolution across the frame.

At the long end resolution and contrast decrease  while purple fringing at high contrast edges becomes obvious.

Focal length E720mm

RAW vs JPG capture  While testing I shot RAW+JPG on every shot. In every case I was able to make a more pleasing picture from the RAW file with Adobe Camera Raw.  

High ISO JPGs showed a posterisation effect on faces in addition to the usual issues with smearing due to noise reduction.

Indoor image quality  The problem is that you want to use an ISO setting greater than base level in order to keep shutter speeds in a reasonable hand  holding range and that impairs picture quality.

The flash can be used but I could find no way to adjust flash output so you get whatever the camera decides. I  find this unsubtle to put it mildly but you do get the shot.

The other approach is to set P Mode  and allow a low minimum shutter speed (this can be user set) of about 1/15 second. This uses a higher ISO but gives a more natural, albeit grainy looking result.  The camera’s OIS seems to manage low shutter speeds quite well at and near the wide end of the zoom.

I found that with some judicious work in Photoshop I got quite decent results up to ISO 800 with even 1600 usable for small prints.

Focal length E65mm. Very nice picture quality at this focal length in bright sun.

Picture quality at the long end of the zoom  The issues here are:

* The widest lens aperture is f6.4

* The OIS is less effective (in my hands anyway) at the long end

* The lens suffers reduced sharpness and contrast. 

However my tests with cameras tripod mounted in controlled conditions with a test chart showed that at Focal Length Equivalent 720mm, the TZ70,  FZ1000 (cropped), Canon SX60 and Nikon P900 each delivered almost identical sharpness and resolution.

So the main issue is camera shake and the quest for ways to minimise this.

* You want to keep the ISO setting at base level if possible but not if that reduces shutter speed too much.

Strategies for the long end 

* You can use a tripod and timer delay. But the whole point of a camera like this is to go lightly with minimum gear and therefore no tripod.  If I were planning to go out with a tripod I would take a more substantial camera.  

By the way, beware the lightweight tripod at full zoom. The slightest breeze will degrade image quality.

* Handhold but make a ‘human tripod’ by holding the camera to the eye, sitting or lying down with elbows resting on knees or other surface and practice mini meditation.

* Practice ways of holding the camera for optimum stability. I found that attaching the camera to a mini tripod then hand holding the camera and tripod together helped to reduce camera shake.

* Set Burst Mode ON. The camera will shoot 8 RAW frames before slowing. My experiments thus far suggest that the second 4 frames tend to be sharper than the first 4. This makes sense as the act of pressing the shutter is one of the causes of camera shake.

* Experiment with shutter speeds around 1/400 second, faster if conditions will allow.

* Use the ‘two foot zoom’ ---go walk closer to your subject if possible.

These strategies help to improve consistency at the long end of the zoom. 

PerformanceThe TZ70 is generally a pleasing performer, responding promptly to user inputs.

Autofocus is prompt, sensitive and accurate, slowing a little at the long end of the zoom and in low light. I tested AF accuracy and found no problems.

Manual focus is possible and assisted by peaking. However the actual process of focussing manually involves much twirling of the lens ring back and forth, often with no definite point of sharp focus evident. 
The rear dial can be used for manual focus.

But most of the time I find autofocus works much better.

The lens zooms from one end to the other in 2 seconds.

Shot to shot time with RAW+ JPG  capture, AF and AE on every frame, is 0.8 seconds.

Shutter response is almost instantaneous if the shot is prefocussed by half pressing the shutter button.

OIS works well especially at the wide end of the zoom where I found handholding at 1/15 second possible.

At the long end (E720mm) I found that if I stood unsupported and held the camera to my eye I could get fairly satisfactory photos from 1/400 second shutter speed.  If I used a different  holding technique with better support I could sometimes get good results with a lower shutter speed.

I tested the TZ70 alongside the Canon SX60 and Nikon P900, both of which had more effective IS/VR than the TZ70 especially around focal length E700mm.

Tripod mounting improved sharpness further.

The TZ70 does enable follow focus on subjects moving towards or away from the camera. I tried it on cars moving towards and away from the camera at about 30 KPH.  At 3 frames per second with AF on each frame and a shutter speed of 1/400 second, I got 70% of frames sharp, 20% slightly unsharp and 8% blurred. Not a bad result.

However with subjects moving across the frame the results were much less satisfactory. The problem is that after the first frame of a burst sequence the EVF shows a review of the previous frame not a preview of the next one. In consequence it is almost impossible to keep the subject accurately in frame.

Panorama  The TZ70 has in camera auto panorama function. It can be configured to sweep horizontally or vertically in landscape or portrait orientation (i.e. total of 4 options). I found it to work quite well in a variety of conditions, producing results suitable for showing on a monitor or social media.
The camera had trouble making smooth curves on architectural subjects but that is quite a common issue with in camera pano functions.

Best results do require some practice and selection of appropriate subjects.

Next: Ergonomics and summary