Tag Archives: 45-85mm

smc Pentax-FA 645 45-85mm f/4.5 lens performance

In the quest for a lens with a focal length that would be considered close to normal, I tried the following two lenses:

  • smc PENTAX-DFA 645 55mm F2.8 AL SDM AW [IF]
  • smc PENTAX-FA 645 45mm F2.8

The first is the lens that was originally released with the Pentax 645D camera. While the image sharpness was fine at the centre, the soft edges were not acceptable for the type of work I do. Same comments are true for the 45mm lens. I returned both and purchased a 45-85mm zoom to see what it can do.

In my blog post on the 45mm fixed lens, I photographed a brick wall to see how the centre versus corner sharpness compared. The same wall is featured below with the 45-85mm set to 45mm and an aperture of f/8. Due to the closer camera to subject distance of the asphalt in the lower corners, I’ve chosen a crop slightly up from the bottom of the frame.

Pentax-FA 645 45-85mm f/4.5 lens shot at 45mm f/8 - overall view

Pentax-FA 645 45-85mm f/4.5 lens shot at 45mm f/8 – overall view

Pentax-FA 645 45-85mm f/4.5 lens shot at 45mm f/8 - top left corner

Pentax-FA 645 45-85mm f/4.5 lens shot at 45mm f/8 – top left corner

Pentax-FA 645 45-85mm f/4.5 lens shot at 45mm f/8 - top right corner

Pentax-FA 645 45-85mm f/4.5 lens shot at 45mm f/8 – top right corner

Pentax-FA 645 45-85mm f/4.5 lens shot at 45mm f/8 - bottom right corner

Pentax-FA 645 45-85mm f/4.5 lens shot at 45mm f/8 – bottom right corner

Pentax-FA 645 45-85mm f/4.5 lens shot at 45mm f/8 - bottom left corner

Pentax-FA 645 45-85mm f/4.5 lens shot at 45mm f/8 – bottom left corner

Pentax-FA 645 45-85mm f/4.5 lens shot at 45mm f/8 - bottom left corner with chromatic aberration adjustment enabled

Pentax-FA 645 45-85mm f/4.5 lens shot at 45mm f/8 – bottom left corner with chromatic aberration adjustment enabled

The crops from this image demonstrate the superior performance of the 45-85mm zoom compared to the 45mm f/2.8 fixed lens. The centre and corners, except for the top right, are consistently sharp and exhibit good detail. Focus was set to Auto as it is generally more reliable than my eye. Camera was on a tripod and ISO was at 200.

The second last image in the series shows the chromatic aberration that can show up with this lens when it is shot at 45mm. Turning on the correction in Adobe Lightroom (same as Adobe Camera Raw) eliminates the colour fringing very effectively. The lens exhibits barrel distortion which can also be removed by enabling the lens corrections.

I was very impressed with the performance of this lens at the wide end of the zoom range. In the more than three years that have elapsed since shooting this test and creating this post, I have shot with this lens extensively. Focusing manually is challenging with the slow maximum aperture, however I have found using autofocus is mostly reliable and any shortcomings in image sharpness have usually been related to insufficient depth of field or not choosing a focus point that maximizes the available depth of field.

 

Trying out the smc Pentax-FA 45-85mm f/4.5 lens

The pause in blog posts has not been due to lack of happenings, but rather quite the opposite. In the past few posts I’d been discussing the challenges in finding a decent mid-range lens for the Pentax 645D. I have written about the older FA 45mm lens. Most users are going to be disappointed by the performance of that lens. Similarly, the new “digitally optimized” 55mm lens also has poor corner sharpness. Twice bitten, now what?

I had read online about some users obtaining good results with the smc Pentax-FA 645 45-85mm f/4.5 zoom lens. This seems to go against the usual wisdom of a prime lens being sharper than a zoom, but I was willing to try anything at this point. My other option was to turn to a Pentax 67 lens with an adapter for the 645D and that was not a road I was interested in traveling just yet.

There is a camera retailer in the U.K that I had purchased my smc Pentax-FA 645 200mm f/4 lens from in December. Great prices and good service. I figured it was worth another email now that I was looking for the 45-85mm lens. Once again, Mifsuds was excellent to deal with and my lens arrived a little more than a week after my email was sent. I normally try to support my local dealers, however going that route in this case would have meant a 3X surcharge.

It’s worth looking at the recent prices on EBay to see what lenses are proving to be popular on the Pentax 645D. The 35mm, 45-85mm and 120mm Macro have all experienced stronger pricing since the 645D became available outside of Japan. It does not appear the 75mm has seen the same increases, although it is an excellent piece of glass as well.

Within a day of it’s arrival, I was out shooting with the 45-85mm lens. It is tougher to focus manually than the 45mm or 55mm lens since its maximum aperture is about one and a half stops smaller. The focus just doesn’t “pop” as well. This is not unique to this lens, however. It’s just a fact of using a slower lens.

So far, I’ve found the 45-85mm to be a good performer with the autofocus system in the 645D. Most images are in the “keeper” category, though keep in mind that I’m mostly shooting subjects that either don’t move or move very slowly. It’s possible to manually focus this lens successfully in good light.

In my next post I’ll show some examples with the 45-85mm. In the meantime, if you’re looking for a mid-range lens for the Pentax 645D, this is the one to go with or should at least deserve your strong consideration.