[Test Express – EN] Objectif Pentax FA ★ 300 f/2.8

FA * 300 f/2.8 et K-1 mk II
Lens test of Pentax FA★ 300 f/2.8 was made with a Pentax K-1 mk II - French version


We were lucky to test this FA ★ 300 f/2 .8. A lens described as a legend by those who have one. A lens whose rating is still very high, close to €uro per gram. But what is it really worth? To answer this question, we tested it in an urban environment. Between the humans and city’s scene, there is already enough to make an opinion. With, to finish, a confrontation with the DA★ 300 f/4.

Presentation of FA ★ 300/2.8

The first impression is that this lens is heavy and bulky. Which is true. The K-1 mk II with the FA ★ 300 weighs just over 4 kg (more than 8 lb 13 oz). It’s not a lens with which you’re going to get around town easily. The photographer gets tired quickly. And he is quickly spotted, sometimes with comments.

This lens is made out of metal of rather silver color (with a touch of green ?). The construction is sturdy, but is not tropicalized (not AW or WR). The single ring is very wide and its touch is correct. In MF mode, it spins « endlessly », even if you can see the limits beyond which spinning is useless. This ring has a dual function. First, by turning it, it allows you to focus in manual mode, and second, by pushing it forward or backward, it allows you to switch to manual or autofocus mode. There is no dedicated AF/MF button.

Double usage de la bague de mise au point
Dual use of the focus ring: by moving it towards the lens, activating manual mode


On the lens, there’s a two-position button. It is a range limiter for focusing, which should allow a more precise and efficient focusing either on a short range (Limit) or on a long range (Full). In use, no real differences in the sharpness of the pictures were found, whatever the position of the limiter.

Caution :

  • The quickshift feature is not available on this lens. There is no need to rotate the focus ring in autofocus mode. Forcing it may damage the mechanism.
  • While holding the lens, it is not uncommon to accidentally move the focus ring and switch from AF mode to MF mode. This is surprising.


Technical data of the FA ★ 300/2.8

  • Focal length (Equivalent to 35mm format) : 300 mm (on APS-C, 455 mm)
  • Mount : KAF
  • Maximum Aperture / Minimum Aperture : 2.8 / 32
  • Minimum Focusing Distance : 2 m
  • Elements / Groups / Number of Diaphragm Blades : 10 elements / 7 groups /8 blades
  • Engine : Screwdrive
  • Others : Internal Focus (IF), rear mount for filters, diaphragm ring
  • Weight : 2765 gr (6 Lb 2 oz) / 3035 gr (6 Lb 11 oz) with lens-hood (270 gr / 9.5 oz)
  • Construction : metal

We appreciate the filter holder which is inserted at the back of the lens, just before the diaphragm ring.Its 43 mm diameter makes it easy to find filters.
A filter for the front lens would have been very expensive (11.2cm diameter)! But because of its position, a circular polarizing filter will not be able to be used.

Porte filtre
filter holder (43mm diameter)
Emplacement porte filtre et bague de diaphragme
Slot for filters and diaphragm ring


This lens benefits from hardware stabilization at the sensor. Its 300 mm focal length requires a minimum shutter speed of 1/300 s without the SR stabilization system. With the latter, tIt’s possible to have a gain between 3 and 5 stops. Or go down to 1/100 s. But given the weight to be carried, even at this speed, an assistance is often necessary (monopod at minimum, tripod is better).

Technical point of view

  • Aberrations (CA) : It’ easy to obtain Chromatic Aberrations with the FA ★ 300. If the circumstances lend themselves to it, they are then very present at large openings. Attenuation from f/5.6, but they persist even at f/11. Be careful, correction profiles often do not exist for post-processing software. It will be necessary to manually correct the CAs.
  • Flare : A relatively flare-resistant lens, even but not perfect. The fault is due to the treatment of SMC type lenses. If this was the best treatment about 40 years ago, it has now become the treatment for « entry-level » Pentax lenses. Satisfactory, but below what HD or Aerobright coatings offer.
  • Image Homogeneity : The homogeneity of the images is constant over the length of the range and regardless of the aperture. At the edge of the field, it remains almost as good as at the centre of the field, and this from f/2.8, which is remarkable.
  • Sharpness : A bit disappointing at f/2.8, where the focus point sometimes lacks sharpness. The problem can be seen when focusing on a very distant point. We don’t have the same problem for close objects. The limit/full button has no effect. Good at f/5.6 and excellent from f/8 to f/16 (see also Notre-Dame de Paris pictures).
FA * 300 à f/2.8
FA * 300 à f/8
FA * 300 à f/2.8
FA * 300 à f/8
  • Distorsion : Very little, nothing to say.
  • Bokeh : Pleasant.

Comparison between FA ★ 300 f/2.8 and DA★ 300 f/4

This comparison between the FA ★ 300 f/2.8 and the DA★ 300 f/4 soon became apparent. Because these 2 lenses are ★, the top of the range at Pentax. They can both be used on a full size body. The DA is recognized as compatible by Ricoh Imaging. There are other points that made us decide to make this comparison, such as :

  • The FA, which hasn’t been manufactured for many years, has a very high second-hand rating (the Pentaxforums website estimates its price at around $2800. In France, August 2020, 2 copies were on sale for a price between 1500 and 1800€, which is already more reasonable). The DA is on sale new at a more reasonable price..
  • FA was designed for Argentine bodies, at a time when the average film offered 5 to 6 million silver grains (often less, rarely more). The first digital ★ range was designed for sensors of up to 30 million photodiodes.
  • Since argentic and digital technologies are different, the optical formulas face different problems in terms of light restitution.

For obvious reasons, this comparison does not provide an image at the f/2.8 aperture. The photos were taken with a Pentax K-1 mk II in Av mode, using a monopod.

FA * 300  DA * 300

You can download full resolution JPEG files here.

This comparison is not to the advantage of the FA on aperture less than f/8. The images offered lack sharpness and homogeneity, unlike the images offered by the DA. At f/8 and above, the lenses converge and at f/11, they are evenly spaced.

FA * 300 f/2.8 et DA * 300 f/4 cote à cote
FA ★ 300 f/2.8 and DA ★  300 f/4 side by side


Incidentally, the difference in weight is such that the DA can be appreciated very quickly. Wearing the FA at arm’s length quickly becomes painful (you can forget the idea of wearing it with the strap around the neck).

PentaxKlub’s opinion

How dare to speak ill of a legendary lens, so popular ? Its odds are not random. It has as much to do with a non-rational feeling of passion as with a rational feeling of rarity. In more ways than one, the FA ★ 300 f/2.8 is exceptional, if only because of its focus and aperture. But it is now showing its limits in the face of ever more powerful sensors and electronics.

Because that’s what it’s all about. The K-1 mk II, the KP and the brand new K-APSC have very powerful calculation units, capable of improving the light captured by the photodiodes. And in doing so, the original specifications of the argentic series ★ are technologically outdated. It’s no coincidence that since the advent of digital technology, Ricoh Imaging is now working on the second version of these numeric specifications.

So the question is whether the FA★ 300 f/2.8 is still an exceptional target. Unfortunately, it used to be, but it is not as exceptional almost 30 years after it was designed. It is still a good, if not a very good goal. But all in all, it is better to buy the DA★ 300, even if its largest aperture is only 4.

However, it is possible that the tested item is faulty. We are ready to test another if it’s loaned to us.

A last word on its price. At $2800 for a used model only, this goal is not a given. And its quality/price ratio is largely negative. Too much for us to recommend you to buy it with your eyes closed. At 1500 €, a favorite purchase can be considered. Provided you find one, because it remains rare on the used market.


This note deserves some explanation. Because the note seems very low. This notation has been achieved with a scale based on lenses designed with current technologies. A scale which is not necessarily suitable for argentic lenses mounted on digital Full Format bodies.

Construction & Finition 6 Exemplary finish for the time
Handling 5 The manipulation of the lens, by its heaviness, penalizes him greatly. Without a monopod or tripod, it is impossible to keep it in hand for a long time. The ingenious filter holder makes him gain 1 point.
Specification (technical) 6 Without an SDM or equivalent motor, the lens is relatively noisy, especially when it starts « pumping » to focus. It is also penalized by the absence of the quickshift feature (which did not exist at the time). On the other hand, the ingenious filter holder makes him gain 1 point.
Image quality (homogeneity, sharpness, distorsion) 35 Good homogeneity (the lack of sharpness is homogeneous) and almost no distortion. Note also that when the focus is on distant objects, there is a significant loss of sharpness before f / 5.6
Optical quality (Aberration, flare, vignetting) 22 This is the problem with this FA, when compared to the current lenses. It is sensitive to flare at full aperture (and sometimes beyond). But above all, it is sensitive to Chromatics Aberrations, due to the absence of current optical or chemical treatments. It loses important points here.
Overall rating 74/100



1/800s à f/3.2, ISO 100
1/800s at f/3.2, ISO 100
1/1000s à f/4, ISO 200
1/1000s at f/4, ISO 200
1/400s à f/3.5, ISO 200
1/400s at f/3.5, ISO 200
1/320s à f/8, ISO 400
1/320s at f/8, ISO 400
1/125s à f/5.6, ISO 100
1/125s at f/5.6, ISO 100
1/2000s à f/2.8, ISO 100
1/2000s at f/2.8, ISO 100
1/1000s à f/3.5, ISO 100
1/2000s at f/2.8, ISO 100
1/320s à f/3, ISO 200
1/320s at f/4, ISO 200


photos by fyve – Click on the pictures to enlarge