Web Analytics RiceHigh's Pentax Blog: June 2020

Monday, June 29, 2020

Pentax Aperture Block Problem Class Action Lawsuit


"A camera owner has filed a class action lawsuit against Ricoh USA Inc. over claims that the company’s line of Pentax camera products are defective in a way that causes them to produce useless, almost completely dark photographs."

Tuesday, June 23, 2020

Unofficial: French D FA* 85/1.4 Special Gallery

(in French)

With both scenery and portrait samples. Unofficial.

Official: D FA* 85mm F1.4 Special Gallery


(in Japanese)

No full or larger size of the photos are available nor those small-sized samples can be downloaded. For that small size of the samples, the image quality of the lens cannot be judged, sad. :-(

A D FA 70-210 F4 Practical Test


Article/Post in Traditional Chinese, but the captions in test photos and crops are self-explanatory.

Sunday, June 07, 2020

New Lens Patent 70-300 F4.5-5.6 with In-lens SR

(in Japanese)

A few key highlights are as follows (Google Translated):

[Name or name] Ricoh Co., Ltd.

However, in the zoom lens system of Patent Document 1, since the second lens group 2b, which is the image blur correction lens group, is close to the stop on the long focal length end side (tele end side), the long focal length end side (tele end is set at the time of image blur correction). The eccentric coma aberration generated on the side) tends to be large. Therefore, the second b group, which is the image blur correction lens group, is composed of three or more lenses, and there remains a problem in weight reduction of the image blur correction lens group.

(Table 5)
Short focal length end Medium focal length Long focal length end
Focal length 72.2 135.0 293.2

F number 4.43 4.88 5.34

(Table 8)
Short focal length end Medium focal length Long focal length end
Focal length 72.0 135.1 293.6

F number 4.59 4.96 5.52

A list of variants of the same design gene are patented. While the focal ranges are almost the same, the maximum apertures could vary a bit but the variations are insignificant.

FA*85 Vs D FA*85 Size Comparison

Tuesday, June 02, 2020

Possible New Optical Designs of the DA*16-50 F2.8 PLM

I recall the old post by the Pentax Rumors about the various new DA 16-50/2.8 lens designs and patent(s) for improved performance, one of which (amongst 10 nos.) would be selected by Pentax for this new lens. Which will they use finally? 16 elements in 13 groups (5 designs), 17 elements in 13 groups (3 designs), 15 elements in 12 groups (two designs)? We shall know by the next year of 2021. :-)

Monday, June 01, 2020

Review of 21mm Full Frame Lens Optical Designs

Pentax DA 21mm F3.2 (APS-C)

Norton 21mm F1.4

Skopar 21mm F4
 Ultron 21mm F1.8

Voigtlander 21mm F1.4

Carl Zeiss 21mm F2.8