Pentax-D FA 100mm Macro – A review

Over the last year I have decided to replace my old rather tired and slow Sigma Macro lenses with a faster and crisper range of Pentax lenses. I really have been blown away by the sharpness of both my 50mm Macro and my latest purchase a Pentax-D FA 100mm Macro, which I am reviewing here. This makes me think that I should have made the swap years ago!

The Pentax-D FA 100mm Macro is currently retailing on Amazon and other online retailers for any where between £400- £549.00 so it really is worth shopping around for the best price. I got lucky back in February 2017 when I purchased mine at the sale price of just £384.96 via Amazon. This was a rare 1st hand purchase for me. Back in my twenties when I was a poor photography student I made it a rule to always buy good quality second hand gear where possible and I still stick by that rule when I can. These days you can often pick up lenses that are ex-display. If you are patient and willing to wait I would recommend keeping an eye on the various online retailers to see what bargains they have. Particularly keep an eye on the retailers who are approved Pentax resellers as they tend to offer the most second hand and ex-display bargains for Pentax users.

So why choose a macro lens? If you want to capture the beauty of objects close-up then macro lenses are ideal as they are optically designed to be sharpest at very close range. As well as producing fantastic life size images of flowers and insects your macro lenses can also be used for other subjects. The 100mm macro for example makes a great portrait lens.

Main Specifications  of the Pentax-D FA 100mm:

Focal length 100mm (equivalent to approx. 153mm
in 35mm format)
Elements in groups 9-8
Angle of view 16° (when attached to PENTAX digital SLR cameras)
24.5° (when attached to PENTAX 35mm SLR cameras)
Aperture f /2.8
Minimum aperture f/32
Mount type KAF-mount
Minimum focus distance 0.303m (0.99ft) (0.130m (0.45ft) working
Maximum magnification 1×
Filter size 49mm
Lens hood PH-RBE 49mm (provided)
Max. Diameter x Length 65mm × 80.5mm (2.6in × 3.2in)
Weight Approx. 340g/12oz. (with hood approx. 380g/


The Pentax-D FA 100mm Macro lens has an aluminium construction with weather resistant seals making it a perfect option for macro photography in unpredictable weather. And you can bet much of the British weather is exactly that! The positioning of optical elements and curvature help to eliminate nearly all flare and ghosting for clearer, high quality images. There is the addition of a lens hood, which is an essential when photographing garden specimens in bright light. Pentax’s multi-layer coating has been added to lower surface reflection, reduce ultraviolet rays, and deliver clear, high-contrast images.


The Pentax-D FA 100mm Macro lens enables close-up photography up to 1x magnification for Life Size images. If you look at the distance scale on the lens you will see above it that the magnification is indicated by denominators such as “1” to indicate “1/1x”, and “5” to indicate “1/5x”. The manual suggests that you can set the magnification first, by turning the focusing ring to set the desired magnification in the manual focus mode. Then focus the subject by moving the camera forward or back. Not sure I have the time or energy to mess about moving the tripod backwards and forwards to get what I want but it sounds like great exercise!

Aperture & Depth of Field:

The minimum aperture is f/2.8 and the maximum is f/32, so plenty of room for creativity. I personally find myself working within the range of f/10 to f/16 with it in the studio and so far I have managed to get some really lovely shots without any loss of detail due to a shallow depth of field. However you do have to be precise with where you focus on your subject in order to maximise the depth of field at the smaller apertures.

Hyacinth on a Black background. Pentax-D FA 100mm Macro. f/16 2.0s

Lens Hood:

This lens does come with a lens hood, which quickly attaches to the end of the lens with one turn. The lens hood is a vital piece of kit for reducing lens flare and really important in situations where you are working against the light. Also on a practical note the lens hood also gives some added protection to the lens. Last year my tripod got knocked over and as my camera headed to the floor I couldn’t catch it before the lens hit the floor first. The lens hood really did save both the lens and camera, and left just a dent in the side of the hood! So speaking from experience I would definitely use your lens hood!

 Chromatic Aberration:

I read a couple of reviews before buying this lens that said it suffered from significant chromatic aberration. I have to say that when I’ve been looking at the images close-up in post-production I haven’t as yet found any significant issues. Some reviewers seem to remain cautious of the lenses quality at f-stop values such as f/2.8 or f/4 for example, so if you work within those ranges this might not be the lens for you. As far as the focus is concerned the Auto-focus is a bit noisy but I don’t really use it, as I prefer to manually focus my work.


Radishes on a green background. f/14 1.3s

Focal Length & Backgrounds:

With the 100mm focal length I really love the fact that I have so much more control over the background in my images. It’s a simple rule to remember – the longer the focal length of the lens is, the narrower the angle of view is. And the narrower the angle of view is, the less coverage behind the subject. This has helped to create some really lovely backgrounds with muted soft tones. This advantage I think works really well with my floral imagery creating an almost paint like quality to the backgrounds and I have found it works well with some of my food imagery where I have wanted to use unusual backgrounds. In this photograph of some radishes for example you can see how the texture of the wood has completely softened in the background, and there is no loss of detail in the top for the radish in the centre of the frame.


In the images below you can see the same subject shot with both the 100mm (on the left) and the 50 mm macro (on the right). There is a lovely soft background in the shot taken with the 100mm, the overall effect is that it concentrates the eye on the subject in the foreground.


So if you are looking to invest in new lenses the Pentax-D FA 100mm Macro is a sound choice when you are working with a limited budget. I think the photography speaks for itself and my investment is already paying its way, giving me greater flexibility and more options for stock imagery assignments.

( Note: the test was carried out using a Pentax K5ii so therefore I am unable to comment on the lenses qualities when used with a full frame camera such as the K1. All my photographs here were shot at ISO 200, using available light through two corner windows.  )

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