K-5: ISO 400 is the New ISO 100

It is midday as I work away at this posting. I have spent the morning taking all kinds of outdoor pictures with my new PENTAX K-5. I don’t have the metrics but there is a good chance I have taken more pictures in the last three days with the new K-5 than I took in the last three months (maybe six months) with my pre-loved K-7. In fact I am even feeling a little guilty that I am ignoring my old faithful K-7 that I was so excited about when I first got it. But the reality is that the K-5, despite the fact it looks exactly the same as the K7, is a massively different (better) camera.

One of the reviews I read leading up to buying the K-5 suggested that as far as digital noise went the K-5’s in-camera JPGs taken at ISO400 were as noise-less (grainy-less) as ISO100 pictures using the K-7. With the limited testing I have done using both cameras I would have to agree with this finding. Pictures taken with the K-5 at ISO400 in daylight might even possibly have less digital noise than ISO100 pictures from the K-7.

If you are lucky enough to own a PENTAX K-5 then, as the reviewer commented, ISO400 is the new ISO100.

So what?

Well the big plus here is that you gain 2 full stops of light—ISO100 to ISO200 is one stop, then ISO200 to ISO400 is another stop; hence 2 full stops. So if you have an f4 lens it basically just became an effective f2 lens. Not an f2.8 lens … but an f2 lens. For anyone who knows anything about lenses and what they cost the difference in cost between a 100mm f4 lens and a 100mm f2 lens is significant; typically at least double the cost. Lenses that let in more light cost (much) more money. As an extreme example the Nikon 85mm f3.5G lens is $749, while the Nikon 85mm f1.4G lens is $2,149—admittedly this is a difference of 2 stops but you get the idea (it is almost three times more expensive).

All of the following pictures were taken at ISO400 using the PENTAX 18-135 DA zoom.


This is the main street of Kalamunda “Village” at 8:21 a.m. Sunday morning the 17th July 2011. It is heavily overcast but even so this picture was taken using f8 at 1/320th. The spot exposure was taken from the centre of the top of the road.


This shot was taken at 8:55 a.m. on a side-road that comes off Pickering Brook Road. It is still overcast (note the lack of strong shadows). Like the shot before this was taken using f8 at 1/320th but this time segmented metering was used.


It is now 9:15 a.m. and I am out on Canning Road south of Kalamunda near Karragullen and this has to be my favourite shots of the morning. This is the JPG directly out of the camera taken at f8 and 1/60th with 28mm of lens. Unlike the shots before it has not been cropped nor has it been sharpened (unsharpened, technically) except for the sort-of-sharpening that occurs when a 4,928 x 3,264 raster is downsized to 650 x 431 to suit my posting size.

At this point the sun is about 80 percent ‘out’ but is still slightly covered by thin cloud. After a little ‘fixing’ up in Photoshop Elements I can see this shot as a canvas print on my wall—not that I have done that yet for any of my pictures (but I am thinking about it).

One of the reasons I like this shot is because of a ‘dream’ picture I have in my mind. I think all us photographers—well those I have talked to anyway—have a dozen or so ‘dream’ pictures stashed away in our heads. Pictures that we want to try and take one day should the planets, the weather, the sun, the time, and a few other things (like a willing model) all happen to line up. My 1 of 12 dream picture has a brightly dressed young girl in the forest, and the forest is dark; darker probably than the ‘forest’ in the picture above (but I can do that with Photoshop). And somehow there is beam light shining on the girl so she glows—her hair glistens and her bright clothing lights up. It might not work! It might be a complete failure! But in my head it is a fantastic picture and I have been carrying it around in my head for about 30 years—one day; one day.

Anyway, the point behind all the pictures in this posting is that they were taken using ISO400, which is probably something I would never normally do except in an emergency—when I just had to get the shot(s) and was willing to accept a degree of noticeable digital noise.

BarryMarkP.S. Sorry to those readers not the least bit interested in photography. That makes two postings in a row about photography, and there is a good chance the next one will be about photography too (especially if I can get SCN to model for me). But it is pretty exciting getting a new camera.