Quick review: Pentax *ist Ds & Sigma 18-50 f/2.8

[kelvin_lau]

I thought I'd share my first impressions of the Pentax *ist DS with

the photo.net community, as I have found this camera quite

remarkable. I have been a dedicated film shooter for several years,

with only brief digital capture experience with a Fuji S2 and a

friend's Canon 10D, both of which were excellent cameras. I

purchased the Pentax *ist Ds outfit in Australia for $1500rrp, which

included a Sigma 18-125 zoom lens, just before I headed off to work

in rural NSW for six months. I purchased it expecting easier use

with just a camera & laptop, rather than have to carry a film

scanner with me (as well as find a convenient lab). I also added a

Sigma DC 18-50mm f/2.8 to the kit.

 

It is a very compact & reasonably lightweight camera, with the

majority of the bulk resulting from the lens rather than the body.

The viewfinder is relatively clear & much larger than the S2 or the

Canon 300D/Rebel, but not quite EOS-1V or Nikon F3 quality. I'd say

it is half way between a Canon consumer DSLR and 35mm EOS viewfinder

in size. Unfortunately the focus point indicators don't seem to be

centred properly (quality control?) although the focusing sensors

seem centred. I've turned off the indicators anyway, as I use

manual focus.

 

Although there is only one command dial, manual shutter & aperture

settings are straightforward - you change the aperture by holding

down the AV button behind the shutter button whilst twirling the

dial. It is more fiddly than a conventional manual film SLR

dial/aperture ring setup, but workable. The available metering modes

are multi-segment, centre weighted & spot, but are only selectable

via the menu. This is irritating when switching between point-and-

shoot mode & manual 'thoughtful' mode, as I prefer multi-segment

when shooting in P and spot mode in M.

 

Autofocus is slow compared to an EOS but on par with the Fuji S2 /

Nikon F80. You can only use Continuous AF by choosing 'Sport' idiot

mode. You can turn the 'ok' button into the AF button (a la Canon

Custom Function 4) but it's pointless, as there are no USM lenses.

I shoot mainly in MF.

 

Like any other digicam, you have to be very careful with your

exposure when shooting high contrast subjects (such as landscapes)

and using JPEG. One day I'll do a pseudo Zone System exposure

latitude test with different colours to see what tone placements are

using the spot meter. It is pretty much the same approach as

shooting slide film - expose for the highlights - except that you

have to watch the shadows too, as they can get mudy too quickly.

 

A quick shoot using ISO3200 revealed loss of definition & shadow

noise - there were a lot of noise reduction artifacts - but if you

compare it to a roll of pushed TMZ3200 or Fuji 1600 it's really not

too bad.

 

All up I have found the *ist Ds an excellent camera for the advanced

photographer who does not intend to enlarge bigger than about

10x15". It is the most compact DLSR available right now &

definitely the cheapest outfit (at least in Australia), allowing

careful manual focus & exposure without compromise. If you are from

the 'smaller is better' school of thought (I prefer using my Leica

M6 over the clunky EOS-1V and Hasselblads purely due to size) then

there really is no other choice. Compact size & excellent

viewfinder make the *ist DS stand out from the crowd.

 

As for the Sigma lenses? The 18-50 f/2.8 seems to be an excellent

lens offering good colour & contrast, with good 'real world'

resolution. I can't comment on distortion or flare yet - that will

have to wait until I shoot more straight-line subjects & backlit

locations. One major problem I have found is difficulty with

achieving good out of focus blur - even at f/2.8 the depth of field

doesn't let me completely blur out the background when shooting some

portraits. I think this is a problem linked entirely to the laws of

optics/physics & common to all small-sensor digital cameras. As for

the 18-125 kit lens - it's not bad (I only have it because you can't

buy the camera here without it) but it tends to stay in the bag most

of the time.

 

To be continued.

[kelvin_lau]

I would also like to add that Pentax added an excellent function when manual metering - you press the AE-L button and it will set the exposure for you. It helps with setting a starting point from which you can very your settings. Very thoughtful.

 

RAW file support from Adobe is still in beta stage (the beta RAW converter will work) - it seems the RAW file is different to the older *ist D.

 

Flash sync is 1/180 and top speed is 1/4000. There is no PC sync socket for studio flash, nor a conventional cable release socket.

 

There is enough eye relief to see the whole frame with eyeglasses. The manual lists 2 other focusing screens (one grid, one cross-hair) but none with microprism or split-image.

 

Feel free to post any other questions about the camera in this thread if you're thinking about buying this camera model & I will have a go at answering them, time permitting.

[jamiew]

Comment:

 

You mention haveing a dedicated AF button is useless becasue Pentax does not have USM. I beleive your point was not USM but rather the full time manual focus option most Canon USM lenses offer (but not all). I say that because if that was your point then you are incorrect becasue Pentax does offer full time manual on their new DA zoom lenses (the kit lens). Also more to the point, the main use for me (I use Canon now) of a dedicated AF button is to separate AF from exposure lock for sports. You want to use AF servo, and follow with AF, but you do not want to set exposure until the time of exposure.

 

Question:

 

When you use AE-L to set exposure when in manual mode, does it set exposure based on the standard program mode, or can you bias it to a certain aperature. In other words if I am set to Av 2.8 and I push AE-L will it try to maintain my Av setting, or just set whatever combination it sees fit. This is a concern because the camera lacks the hyper program mode of the IstD

[kelvin_lau]

That's correct Jamie, I was referring more to the full-time manual focus feature available to Canon lenses. I wasn't aware that Pentax had the feature available to some of their newer lenses - in which case the 'OK' button AF function makes more sense.

 

I am not familiar with Hyper Manual so I can't comment on that, but when you use the AE-L button in manual exposure mode it seems to decide on its own shutter-aperture combination, probably based on its own AE program. You can't bias it towards one end or the other. When using TV or AV mode it functions normally as an AE Lock button.

[john_bean]

The AEL button in manual mode does one of two things:

 

1. With aperture ring in "A" position (or lenses with no aperture ring) it sets the same exposure as you would get in program mode.

 

2. With aperture ring in any other position, or with any pre-A lens it performs stop-down metering and sets the shutter speed accordingly.