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Pentax K-5 Review – High ISO NR

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Overview

Pentax K-5 High ISO Noise Reduction

The Pentax K-5 offers an unusually flexible amount of control over noise reduction applied to its JPEGs. In addition to "Auto", you can adjust how much NR is applied ("Off", "Low", "Medium" or "High") at all ISOs, or you can select "Custom" which allows you to choose from the same four options at each ISO sensitivity setting in whole EV increments. That is, if you enable 1/3 EV ISO steps, you get one NR setting for ISO 80, another for ISO 100, 125, and 160, another for ISO 200, 250, and 320, etc. The same applies for 1/2 EV ISO steps, but with only two sensitivities sharing each setting (ie. ISO 80 gets one itself, ISO 100 and 140 share a setting, ISO 200 and 280 share one, etc.). Kudos to Pentax to providing such excellent control over noise reduction for JPEGs, though as you can see from the crops below, the "Off" setting does not disable noise reduction at higher ISOs.

See for yourself how the Pentax K-5's four noise reduction levels work under daylight-balanced lighting. Click on any of the crops below to see the corresponding full-sized image.

High ISO Noise Reduction Settings Comparison
Daylight-balanced illumination
Off
Low
Medium
High
I
S
O

8
0
0
 Pentax K-5 Overview image 1 Pentax K-5 Overview image 2 Pentax K-5 Overview image 3 Pentax K-5 Overview image 4
Pentax K-5 Overview image 5 Pentax K-5 Overview image 6 Pentax K-5 Overview image 7 Pentax K-5 Overview image 8
Pentax K-5 Overview image 9 Pentax K-5 Overview image 10 Pentax K-5 Overview image 11 Pentax K-5 Overview image 12
Off
Low
Medium
High
I
S
O

1
6
0
0
 Pentax K-5 Overview image 13 Pentax K-5 Overview image 14 Pentax K-5 Overview image 15 Pentax K-5 Overview image 16
Pentax K-5 Overview image 17 Pentax K-5 Overview image 18 Pentax K-5 Overview image 19 Pentax K-5 Overview image 20
Pentax K-5 Overview image 21 Pentax K-5 Overview image 22 Pentax K-5 Overview image 23 Pentax K-5 Overview image 24
Off
Low
Medium
High
I
S
O

3
2
0
0
 Pentax K-5 Overview image 25 Pentax K-5 Overview image 26 Pentax K-5 Overview image 27 Pentax K-5 Overview image 28
Pentax K-5 Overview image 29 Pentax K-5 Overview image 30 Pentax K-5 Overview image 31 Pentax K-5 Overview image 32
Pentax K-5 Overview image 33 Pentax K-5 Overview image 34 Pentax K-5 Overview image 35 Pentax K-5 Overview image 36
Off
Low
Medium
High
I
S
O

6
4
0
0
 Pentax K-5 Overview image 37 Pentax K-5 Overview image 38 Pentax K-5 Overview image 39 Pentax K-5 Overview image 40
Pentax K-5 Overview image 41 Pentax K-5 Overview image 42 Pentax K-5 Overview image 43 Pentax K-5 Overview image 44
Pentax K-5 Overview image 45 Pentax K-5 Overview image 46 Pentax K-5 Overview image 47 Pentax K-5 Overview image 48
Off
Low
Medium
High
I
S
O

1
2
8
0
0
 Pentax K-5 Overview image 49 Pentax K-5 Overview image 50 Pentax K-5 Overview image 51 Pentax K-5 Overview image 52
Pentax K-5 Overview image 53 Pentax K-5 Overview image 54 Pentax K-5 Overview image 55 Pentax K-5 Overview image 56
Pentax K-5 Overview image 57 Pentax K-5 Overview image 58 Pentax K-5 Overview image 59 Pentax K-5 Overview image 60
Off
Low
Medium
High
I
S
O

2
5
6
0
0
 Pentax K-5 Overview image 61 Pentax K-5 Overview image 62 Pentax K-5 Overview image 63 Pentax K-5 Overview image 64
Pentax K-5 Overview image 65 Pentax K-5 Overview image 66 Pentax K-5 Overview image 67 Pentax K-5 Overview image 68
Pentax K-5 Overview image 69 Pentax K-5 Overview image 70 Pentax K-5 Overview image 71 Pentax K-5 Overview image 72
Off
Low
Medium
High
I
S
O

5
1
2
0
0
 Pentax K-5 Overview image 73 Pentax K-5 Overview image 74 Pentax K-5 Overview image 75 Pentax K-5 Overview image 76
Pentax K-5 Overview image 77 Pentax K-5 Overview image 78 Pentax K-5 Overview image 79 Pentax K-5 Overview image 80
Pentax K-5 Overview image 81 Pentax K-5 Overview image 82 Pentax K-5 Overview image 83 Pentax K-5 Overview image 84

The above crops show the effects of the 4 levels of high ISO noise reduction, under our studio HMI lighting we use to simulate daylight. The Medium setting strikes a good balance between noise and detail, however subtle detail in the red cloth swatch starts to suffer already at ISO 800. It's interesting that at ISO 800 and 1600, the "Off" setting does leave more detail (and chroma noise), but at higher ISOs, it appears to be applying at least as much noise reduction as the "Low" setting, if not more.

How does the Pentax K-5's JPEGs compare to state-of-the-art APS-C models with similar resolution at high ISOs? See the following table which compares at the default noise reduction setting.

High ISO Comparison with
Canon 60D, Nikon D7000 and Sony A580
(All default noise reduction)
Daylight-balanced illumination
Pentax K-5
Canon 60D
Nikon D7000
Sony A580
I
S
O

8
0
0
 Pentax K-5 Overview image 85 Pentax K-5 Overview image 86 Pentax K-5 Overview image 87 Pentax K-5 Overview image 88
Pentax K-5 Overview image 89 Pentax K-5 Overview image 90 Pentax K-5 Overview image 91 Pentax K-5 Overview image 92
Pentax K-5 Overview image 93 Pentax K-5 Overview image 94 Pentax K-5 Overview image 95 Pentax K-5 Overview image 96
Pentax K-5
Canon 60D
Nikon D7000
Sony A580
I
S
O

1
6
0
0
 Pentax K-5 Overview image 97 Pentax K-5 Overview image 98 Pentax K-5 Overview image 99 Pentax K-5 Overview image 100
Pentax K-5 Overview image 101 Pentax K-5 Overview image 102 Pentax K-5 Overview image 103 Pentax K-5 Overview image 104
Pentax K-5 Overview image 105 Pentax K-5 Overview image 106 Pentax K-5 Overview image 107 Pentax K-5 Overview image 108
Pentax K-5
Canon 60D
Nikon D7000
Sony A580
I
S
O

3
2
0
0
 Pentax K-5 Overview image 109 Pentax K-5 Overview image 110 Pentax K-5 Overview image 111 Pentax K-5 Overview image 112
Pentax K-5 Overview image 113 Pentax K-5 Overview image 114 Pentax K-5 Overview image 115 Pentax K-5 Overview image 116
Pentax K-5 Overview image 117 Pentax K-5 Overview image 118 Pentax K-5 Overview image 119 Pentax K-5 Overview image 120
Pentax K-5
Canon 60D
Nikon D7000
Sony A580
I
S
O

6
4
0
0
 Pentax K-5 Overview image 121 Pentax K-5 Overview image 122 Pentax K-5 Overview image 123 Pentax K-5 Overview image 124
Pentax K-5 Overview image 125 Pentax K-5 Overview image 126 Pentax K-5 Overview image 127 Pentax K-5 Overview image 128
Pentax K-5 Overview image 129 Pentax K-5 Overview image 130 Pentax K-5 Overview image 131 Pentax K-5 Overview image 132
Pentax K-5
Canon 60D
Nikon D7000
Sony A580
I
S
O

1
2
8
0
0
 Pentax K-5 Overview image 133 Pentax K-5 Overview image 134 Pentax K-5 Overview image 135 Pentax K-5 Overview image 136
Pentax K-5 Overview image 137 Pentax K-5 Overview image 138 Pentax K-5 Overview image 139 Pentax K-5 Overview image 140
Pentax K-5 Overview image 141 Pentax K-5 Overview image 142 Pentax K-5 Overview image 143 Pentax K-5 Overview image 144
Pentax K-5
Canon 60D
Nikon D7000
Sony A580
I
S
O

2
5
6
0
0
 Pentax K-5 Overview image 145
N/A
ISO 25,600
Not Supported
 Pentax K-5 Overview image 146
N/A
ISO 25,600
Not Supported
Pentax K-5 Overview image 147
N/A
ISO 25,600
Not Supported
 Pentax K-5 Overview image 148
N/A
ISO 25,600
Not Supported
Pentax K-5 Overview image 149
N/A
ISO 25,600
Not Supported
 Pentax K-5 Overview image 150
N/A
ISO 25,600
Not Supported
Pentax K-5
Canon 60D
Nikon D7000
Sony A580
I
S
O

5
1
2
0
0
 Pentax K-5 Overview image 151
N/A
ISO 51,200
Not Supported
N/A
ISO 51,200
Not Supported
N/A
ISO 51,200
Not Supported
Pentax K-5 Overview image 152
N/A
ISO 51,200
Not Supported
N/A
ISO 51,200
Not Supported
N/A
ISO 51,200
Not Supported
Pentax K-5 Overview image 153
N/A
ISO 51,200
Not Supported
N/A
ISO 51,200
Not Supported
N/A
ISO 51,200
Not Supported

All four cameras in this group show similar levels of noise at ISO 800 with the Canon 60D and Sony A580 showing a touch less, but the latter are starting to blur tone-on-tone detail in the red leaf fabric. At higher ISOs, the Nikon D7000 starts to pull away from the pack in terms of low contrast detail, with the others applying stronger chroma noise reduction. However, the K-5 and 60D both do a slightly better job at keeping higher-contrast detail more clearly defined. It's also no surprise that the 18-megapxel Canon 60D outresolves the other three which all have 16-megapixel sensors. All-in-all, a very good performance from the Pentax K-5.

Here's a comparison of the K-5 with its predecessor, as well as other semi-professional models:

High ISO Comparison with
Pentax K-7, Canon 7D and Nikon D300S
(All default noise reduction)
Daylight-balanced illumination
Pentax K-5
Pentax K-7
Canon 7D
Nikon D300S
I
S
O

8
0
0
 Pentax K-5 Overview image 154 Pentax K-5 Overview image 155 Pentax K-5 Overview image 156 Pentax K-5 Overview image 157
Pentax K-5 Overview image 158 Pentax K-5 Overview image 159 Pentax K-5 Overview image 160 Pentax K-5 Overview image 161
Pentax K-5 Overview image 162 Pentax K-5 Overview image 163 Pentax K-5 Overview image 164 Pentax K-5 Overview image 165
Pentax K-5
Pentax K-7
Canon 7D
Nikon D300S
I
S
O

1
6
0
0
 Pentax K-5 Overview image 166 Pentax K-5 Overview image 167 Pentax K-5 Overview image 168 Pentax K-5 Overview image 169
Pentax K-5 Overview image 170 Pentax K-5 Overview image 171 Pentax K-5 Overview image 172 Pentax K-5 Overview image 173
Pentax K-5 Overview image 174 Pentax K-5 Overview image 175 Pentax K-5 Overview image 176 Pentax K-5 Overview image 177
Pentax K-5
Pentax K-7
Canon 7D
Nikon D300S
I
S
O

3
2
0
0
 Pentax K-5 Overview image 178 Pentax K-5 Overview image 179 Pentax K-5 Overview image 180 Pentax K-5 Overview image 181
Pentax K-5 Overview image 182 Pentax K-5 Overview image 183 Pentax K-5 Overview image 184 Pentax K-5 Overview image 185
Pentax K-5 Overview image 186 Pentax K-5 Overview image 187 Pentax K-5 Overview image 188 Pentax K-5 Overview image 189
Pentax K-5
Pentax K-7
Canon 7D
Nikon D300S
I
S
O

6
4
0
0
 Pentax K-5 Overview image 190 Pentax K-5 Overview image 191 Pentax K-5 Overview image 192 Pentax K-5 Overview image 193
Pentax K-5 Overview image 194 Pentax K-5 Overview image 195 Pentax K-5 Overview image 196 Pentax K-5 Overview image 197
Pentax K-5 Overview image 198 Pentax K-5 Overview image 199 Pentax K-5 Overview image 200 Pentax K-5 Overview image 201
Pentax K-5
Pentax K-7
Canon 7D
Nikon D300S
I
S
O

1
2
8
0
0
 Pentax K-5 Overview image 202
N/A
ISO 12,800
Not Supported
 Pentax K-5 Overview image 203
N/A
ISO 12,800
Not Supported
Pentax K-5 Overview image 204
N/A
ISO 12,800
Not Supported
 Pentax K-5 Overview image 205
N/A
ISO 12,800
Not Supported
Pentax K-5 Overview image 206
N/A
ISO 12,800
Not Supported
 Pentax K-5 Overview image 207
N/A
ISO 12,800
Not Supported
Pentax K-5
Pentax K-7
Canon 7D
Nikon D300S
I
S
O

2
5
6
0
0
 Pentax K-5 Overview image 208
N/A
ISO 25,600
Not Supported
N/A
ISO 25,600
Not Supported
N/A
ISO 25,600
Not Supported
Pentax K-5 Overview image 209
N/A
ISO 25,600
Not Supported
N/A
ISO 25,600
Not Supported
N/A
ISO 25,600
Not Supported
Pentax K-5 Overview image 210
N/A
ISO 25,600
Not Supported
N/A
ISO 25,600
Not Supported
N/A
ISO 25,600
Not Supported
Pentax K-5
Pentax K-7
Canon 7D
Nikon D300S
I
S
O

5
1
2
0
0
 Pentax K-5 Overview image 211
N/A
ISO 51,200
Not Supported
N/A
ISO 51,200
Not Supported
N/A
ISO 51,200
Not Supported
Pentax K-5 Overview image 212
N/A
ISO 51,200
Not Supported
N/A
ISO 51,200
Not Supported
N/A
ISO 51,200
Not Supported
Pentax K-5 Overview image 213
N/A
ISO 51,200
Not Supported
N/A
ISO 51,200
Not Supported
N/A
ISO 51,200
Not Supported

Here, we can see just how much better the Pentax K-5 is over its predecessor, the K-7, and the improvement over the older generation sensors and/or processing of the Canon 7D and Nikon D300S. Note that the K-5's overzealous chroma noise reduction is rendering the blue text in the scale almost as monochrome at very high ISOs.

See the High ISO RAW crops page, which is a much better indication of relative sensor performance.