Pentax Optio 750Z Review
Timing & Performance
The 750Z's retro looks appear to echo parts of its performance. The 3.6 second startup feels like a very long time and once on it does seem to take another second or so to 'ready' itself before you can take a shot (4.8 seconds off to shot taken is slow these days). The 750Z was another camera which had a tendency to get into an AF hunt in mid to low light or at telephoto, waiting for over two seconds to see if it's actually going to get a lock isn't fun. Also poor is the camera's buffer size and continuous shooting (if you can really call it that). Overall the 750Z is usable but never feels quick.
All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 3056 x 2296 JPEG image (approx. 2,600 KB per image).
Media used for these tests
- 512 MB SanDisk Extreme SD card
- 512 MB Lexar 32x High-Speed SD card
|Power: Off to Record||Live view||3.6||3.6|
|Power: Record to Off||3.1||3.1|
|Mode: Record to Play||Image displayed||1.8||1.8|
|Mode: Play to Record||Live view||1.2||1.2|
|Play: Magnify||To 10x magnification||6.3||6.3|
|Play: Thumbnail view||3 x 3 thumbnails||1.5||1.5|
|Half-press Lag (0->S1)||Wide angle (Wide AF Area)||0.5 - 1.5|
|Half-press Lag (0->S1)||Wide angle (Spot AF Area)||0.6 - 2.0|
|Half-press Lag (0->S1)||Telephoto (Wide AF Area)||0.6 - 2.5|
|Half-press Lag (0->S1)||Telephoto (Spot AF Area)||0.7 - 2.5|
|Half to Full-press Lag (S1->S2)||Viewfinder||0.1|
|Half to Full-press Lag (S1->S2)||LCD Monitor||0.1|
|Full-press Lag (0->S2)||Wide angle (Wide AF Area)||0.6|
|Off to Shot Taken||Wide angle (Wide AF Area)||4.8|
|Shot to Shot||Record review On||2.2|
|Shot to Shot||Record review Off||2.0|
Lag Timing Definitions
|Half-press Lag (0->S1)
Many digital camera users prime the AF and AE systems on their camera by half-pressing the shutter release. This is the amount of time between a half-press of the shutter release and the camera indicating an auto focus & auto exposure lock on the LCD monitor / viewfinder (ready to shoot).
|Half to Full-press Lag (S1->S2)
The amount of time it takes from a full depression of the shutter release button (assuming you have already primed the camera with a half-press) to the image being taken.
(Take shot, AF/AE primed)
|Full-press Lag (0->S2)
The amount of time it takes from a full depression of the shutter release button (without performing a half-press of the shutter release beforehand) to the image being taken. This is more representative of the use of the camera in a spur of the moment 'point and shoot' situation.
(Take shot, AF/AE not primed)
The tables below show the results of our continuous shooting test, indicating the actual frame rate along with maximum number of frames and how long you would have to wait after taking the maximum number of frames before you could take another shot. Media used for these tests was a 512 MB Lexar 32x High-Speed SD card. Shutter speed was kept above 1/250 sec during these tests.
Frames in one burst
|3056 x 2296 JPEG||1.0 fps||5||4.5 sec|
|3056 x 2296 JPEG||1.0 fps||11||3.1 sec|
|2048 x 1536 JPEG||1.0 fps||13||3.2 sec|
|*1||You can take a frame as soon as there is space in the cameras internal buffer (writing continues "in the background").|
Just one frame per second and only eleven images in 'standard' () image quality mode, it's a bit disappointing. In reality the 750Z lags behind its quoted performance of 'approximately 1.3 fps' and doesn't have a big enough buffer to provide a useful continuous shooting capability.
File Write / Display and Sizes
Timings shown below are the time taken for the camera to process and "flush" the image out to the storage card, the timer was started as soon as the shutter release was pressed and stopped when activity indicator beside the viewfinder had gone out. This means the timings also include the cameras processing time and as such are more representative of the actual time to "complete the task".
Media used for these tests
- 512 MB SanDisk Extreme SD card
- 512 MB Lexar 32x High-Speed SD card
|Image Type||Time to write, secs *1||Time to display, secs *2|
|3056 x 2296 TIFF||11.8||12.1||6.9||6.8|
|3056 x 2296 JPEG||3.2||3.4||1.8||1.6|
|3056 x 2296 JPEG||2.8||2.8||1.4||1.3|
|2048 x 1536 JPEG||2.8||2.8||1.2||1.2|
|*1||As with most digital cameras there is a delay before the actual media write begins, the timings above include this delay (as they're taken from the shutter release). For JPEG images this appears to be around 1.4 sec, for TIFF around 4.5 sec. Hence you must subtract this from the figures above to get the actual media write time.|
|*2||The camera displays a 'rough image' almost immediately and then takes the measured amount of time to load the full resolution image and display it. This full resolution image is of course also required if you wish to magnify.|
|Image Type||File size
|Images on a
512 MB Card
|3056 x 2296 TIFF||20,668 KB||24|
|3056 x 2296 JPEG||2,500 KB||124|
|3056 x 2296 JPEG||1,500 KB||248|
|2048 x 1536 JPEG||1,500 KB||277|
The 750Z continues to write in the background and so the live view returns approximately 1.6 seconds after taking a shot (except for TIFF which locks the camera until completed). This means you can almost always take the next shot even if something is still in the camera's buffer. Write speed was above average and about what we expect of a camera at this level, there also appeared to be little performance difference between the SanDisk and Lexar cards.
Low Light Auto Focus
This test is designed to measure the minimum amount of light under which the camera can still focus. The focus target is our lens distortion test chart (shown here on the right), camera is positioned exactly 2 m (6.6 ft) away.
Light levels are gradually dropped until the camera can no longer focus. This is carried out at both wide angle and telephoto zoom positions (as more light reaches the focusing systems with a larger aperture).
at focal len.
AF Assist Lamp
Lowest light focus
|Wide (37.5 mm equiv.)||F2.8||On||0.2 EV|
|Wide (37.5 mm equiv.)||F2.8||Off||3.3 EV|
|Tele (187.5 mm equiv.)||F4.6||On||Complete Darkness|
|Tele (187.5 mm equiv.)||F4.6||Off||2.3 EV|
|Light intensity (Lux) = 2.5 x 2^EV (@ ISO 100), 10.76391 Lux = 1 foot-candle (fc)|
It has to be said that the 750Z's low light auto focus was disappointing, despite the AF assist lamp the camera still needed some additional ambient light to produce enough contrast for the AF system. Without the AF assist lamp the 750Z needs a moderately light scene before it will reliably (and repeatedly) lock AF.
We ran the camera through our new battery life test. This test is designed to be fair and comparative to each camera and battery type:
- Take 4 shots without flash
- Wait 2 minutes (50% of the time powering the camera off)
- Take 1 shot with flash
- Wait 1 minute
Batteries are fully discharged and recharged before the test and all cameras were reset to their factory default settings. Here are the results:
Prosumer / SLR-Like
|Battery||Power||Battery life||Number of shots|
|Minolta DiMAGE 7||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||1 hr 14 mins||125|
|Minolta DiMAGE 5||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||1 hr 56 mins||195|
|Nikon Coolpix 5700||EN-EL1||4.8 Wh||2 hr 08 mins||215|
|Canon PowerShot S40||NB-2L||3.9 Wh||2 hr 13 mins||225|
|Minolta DiMAGE S304||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||2 hr 18 mins||235|
|Canon PowerShot S45||NB-2L||3.9 Wh||2 hr 28 mins||240|
|Nikon Coolpix 4500||EN-EL1||4.8 Wh||2 hr 27 mins||250|
|Fujifilm FinePix 6900Z||NP-80||4.1 Wh||2 hr 29 mins||250|
|Nikon Coolpix 990||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||2 hr 30 mins||255|
|Nikon Coolpix 995||EN-EL1||4.8 Wh||2 hr 30 mins||255|
|Nikon Coolpix 5000||EN-EL1||4.8 Wh||2 hr 32 mins||260|
|Minolta DiMAGE 7Hi||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||2 hr 33 mins||260|
|Canon PowerShot Pro1||BP-511A||10.2 Wh||2 hr 36 mins||265|
|Canon PowerShot S50||NB-2L||3.9 Wh||2 hr 39 mins||270|
|Minolta DiMAGE S404||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||2 hr 39 mins||270|
|Sony DSC-V1||NP-FC11||2.8 Wh||2 hr 39 mins||270|
|Olympus C-7000 Zoom||LI-12B||4.5 Wh||2 hr 44 mins||280|
|Nikon Coolpix 8700||EN-EL1||5.0 Wh||2 hr 45 mins||280|
|Minolta DiMAGE 7i||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||2 hr 46 mins||270|
|Olympus E-20||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||2 hr 48 mins||285|
|Canon PowerShot G1||BP-511||8.1 Wh||3 hr 00 mins||300|
|Nikon Coolpix 5400||EN-EL1||4.8 Wh||3 hr 06 mins||315|
|HP Photosmart 850||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||3 hr 12 mins||325|
|Sony DSC-S75||NP-FM50||8.6 Wh||3 hr 15 mins||330|
|Nikon Coolpix 8800||EN-EL7||8.1 Wh||3 hr 27 mins||350|
|Fujifilm FinePix S602Z||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||3 hr 29 mins||350|
|Canon PowerShot G2||BP-511||8.1 Wh||3 hr 32 mins||355|
|Casio QV-4000||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||3 hr 38 mins||365|
|Olympus C-5050 Zoom||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||3 hr 48 mins||380|
|Casio EXILIM EX-P700||NP-40||4.5 Wh||3 hr 48 mins||385|
|Sony DSC-S85||NP-FM50||8.6 Wh||3 hr 50 mins||400|
|Sony DSC-F717||NP-FM50||8.6 Wh||4 hr 02 mins||405|
|Pentax Optio 750Z||D-LI7||6.6 Wh||4 hr 03 mins||415|
|Sony DSC-V3||NP-FR1||4.4 Wh||4 hr 05 mins||415|
|Nikon Coolpix 8400||EN-EL7||8.1 Wh||4 hr 09 mins||420|
|Sony DSC-F707||NP-FM50||8.6 Wh||4 hr 20 mins||440|
|Fujifilm S7000 Zoom||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||4 hr 23 mins||445|
|Konica Minolta DiMAGE A2||NP-400||11.1 Wh||4 hr 26 mins||450|
|Canon PowerShot G3||BP-511||8.1 Wh||4 hr 32 mins||455|
|Canon PowerShot G5||BP-511||8.1 Wh||4 hr 33 mins||460|
|Pentax Optio 550||D-LI7||6.6 Wh||4 hr 36 mins||465|
|Minolta DiMAGE A1||NP-400||11.1 Wh||5 hr 02 mins||515|
|Leica Digilux 2||BP-DC1-E||10.1 Wh||5 hr 05 mins||515|
|Sony DSC-F828||NP-FM50||8.6 Wh||5 hr 28 mins||540|
|Fujifilm FinePix S5000||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||5 hr 31 mins||555|
|Canon PowerShot G6||BP-511A||10.3 Wh||5 hr 38 mins||570|
|Olympus C-8080 WZ||BLM-1||10.8 Wh||5 hr 52 mins||595|
|Other test notes:|
| LCD monitor is left on during
the battery test
The camera is powered off half of the time and left on half of the time (switch every 10 iterations)
There are now higher capacity AA NiMH batteries available, however in the interests of fair
comparison we will continue to use our 1600 mAh test set
The Optio 750Z's larger-than-average battery (6.6 Wh) helped it to a four hour performance in our battery tests, very good although less than the Optio 550 did with the same battery. We did note that the camera body got quite warm left switched on.
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