Generally, some of the advantages of the Olympus Stylus 840 compared to other compact competitors include: it is much smaller (compact (96×57×24 mm) vs compact (130×64×28 mm)), has better image stabilization (lens vs none), is slightly lighter (170 g vs 224 g) and has a faster max shutter speed (1/2000 of a second vs 1/1000 of a second).
However, on average it has a much narrower wide angle lens (36 mm vs 21 mm), slightly lower maximum light sensitivity (1,600 ISO vs 6,400 ISO), doesn't have a screen which flips out, has a CCD-family sensor (CCD vs CMOS) and is older (january 2008 vs february 2015).
Olympus Stylus 810
2 years older
Significant advantages of the Stylus 810 (vs the Stylus 840)
Significant disadvantages of the Stylus 810 (vs the Stylus 840)
- No image stabilization: None vs
- Lens
- Significantly smaller screen: 2.5" vs 2.7"
- Much slower max shutter speed: 1/1000 of a second vs 1/2000 of a second
common strengths of the Stylus 810 and Stylus 840
- Very small: Super compact (97×56×23 mm) vs Compact (96×57×24 mm)
- Very thin: 0.9" vs 0.9"
- Very light: 165 g vs 170 g
Olympus Stylus Tough TG-860
7 years newer
$324
Significant advantages of the TG-860 (vs the Stylus 840)
- Much better wide angle: 21 mm vs 36 mm
- Has a CMOS-family sensor: CMOS vs CCD
- Much larger screen: 3" vs 2.7"
Significant disadvantages of the TG-860 (vs the Stylus 840)
- Much larger: Compact (130×64×28 mm) vs Compact (96×57×24 mm)
- Significantly heavier: 224 g vs 170 g
common strengths of the TG-860 and Stylus 840
- Good image stabilization:
- Lens
vs - Lens
- Thin: 1.1" vs 0.9"