Playing With Lenses

Tuesday, 16 January 2018

Nice getting to know you: Pentax-A Zoom 1:3.5-4.5 28-80mm

Cost: $24 (average market price $29.33)

Let's state from the beginning that there is a coated SMC version of this lens that should achieve better image quality. As this is an early zoom lens, I was not expecting to much, and my first photos seemed to confirm that sentiment. But, as I was using the lens during two shoots, it was starting to grow on me.

It's a smooth two-touch zoom lens that was pleasant to use. Easy to focus, easy to zoom. Worked well with the peak focus feature of the Sony a6000. The lens looked well used, but everything was still working as it was coming out of the factory. A testament to the quality build of these old Pentax lenses.

This lens is capable of reasonable sharpness across the whole image, especially when use at the outer edges of the range, and stopped down a few steps. Color is good, although some editing was required to make the colors pop. Even without SMC coating, the lens had little aberration, unless when used taking pictures in the direction of the sun.

So, nothing special, but for the low cost, it's not a bad lens. A good walk-around lens, with some occasional light macro work. A welcome addition to my Pentax collection that is still growing on me.
Lens Specification:

Focal Length: 28-80mm
Maximum Aperture: F3.5
Minimum Aperture: F22
Image Format: 35mm
Lens Mount: PK
Optics: 8 elements in 8 groups
Blades: 8
Focussing: Manual
Minimum Focus: 100cm
Filter Size: 58mm
Weight: 434g
Length: 80-94mm
Production: 1989 to1994
Serial Number: 6870366
Made in: Taiwan
More information on Pentax

Samples:

Pictures taken with Lens Turbo II Adapter

1/1250 sec - ISO100 - Handheld

1/3200 sec - ISO100 - Handheld - Cropped

1/1250 sec - ISO100 - Handheld

1/200 sec - ISO800 - Handheld

1/800 sec - ISO400 - Handheld

1/200 sec - ISO400 - Handheld

1/60 sec - ISO400 - Handheld

Sources:

Wikipedia: Pentax

Pentaxforums

Boijdar Dimitrov's Pentax K-mount Page

Sunday, 14 January 2018

Slippin'n sliding: Sigma Zoom AF-B 1:4-5.6 60-200mm

Cost: $19.99 (average market price $12)

This seems to be an obscure Sigma lens as there is almost no information to find, and it was only in production for one year, so likely not to many samples were made, but it also exists in a manual focus version. On my Sony a600, used with a non electronic Minolta AF-NEX adapter, I have to focus manually. So my review does not include any statement on how well it can auto-focus.

When handling the lens, I started to understand why it was only in production for a year. It kind of sucked... The lens mount is very loosely attached to the lens, although that might be a problem specific to this copy, it sure made for a very wobbly lens. A bigger problem is the zoom creep. This lens is a simple push/pull design, and on the heavy side. When pointing downwards, the outer barrel slowly slides to the maximum tele-end of the lens. It makes this lens unusable for macro, or any situation where you have to point down. The manual focus ring is very slim (the cartled front side of the lens), giving little grip, and the focussing itself has little resistance, making accurate focus difficult to do.

Image quality is nothing special. Regular sharpness, reasonable color, no extensive color fringing. But I did like the smooth bokeh. One other major problem... not sure if it was the adapter, or the lens, but I was not able to get infinity focus. It was just a little out of reach.

So, definitely not a keeper. But for someone who does have a compatible camera with autofocus, it might actually work as a low-market option to reach 200mm. But for me, the slippin'n sliding outer barrel was a deal breaker.

Lens Specification:

Focal Length: 60-200mm
Maximum Aperture: F4
Minimum Aperture: F22
Image Format: 35mm
Lens Mount: AF
Optics: 12 elements in 9 groups
Blades: 6
Focussing: Manual & Auto Focus
Minimum Focus: 150cm
Filter Size: 52mm Weight: 497g
Length: 84-123mm
Production: 1986-1987
Serial Number: 1001737
Made in: Japan

More information on: Sigma Corporation

Samples:

1/160 sec - ISO1600 - Handheld

1/320 sec - ISO1600 - Handheld

1/80 sec - ISO1000 - Handheld

1/320 sec - ISO1600 - Handheld

1/160 sec - ISO1600 - Handheld

1/320 sec - ISO1600 - Handheld

1/160 sec - ISO1600 - Handheld

1/800 sec - ISO1600 - Handheld

Sources:History of Sigma Lenses

Sunday, 24 December 2017

Something on Starbursts

I love starbursts! On sinking sun, on a night street light or just a little glitter in the background.
You might know that there are at least two common ways to create the starburst effect in a photo.

First one is by using a Cross Screen filter, reviewed in an earlier blog on the Hoya CS. These typically give you longer rays, and the ability to choose the angle of the rays.

Starburst by using Hoya CS Filter

The other ways to create starbursts is by selecting a very small aperture, where the rays are created by light diffraction in the corner between two aperture blades.

What is less known is how to control the number of rays within your starburst. One corner between two blades creates two rays. One stronger one in the corner where two blades meet, and one less stronger one at the opposite side. The more blades in a lens, the more corners between blades, the more rays you will see in the photo.

If you have an even number of blades, the ray on the other side will overlap with the ray caused by the opposite corner of two different blades. If you have uneven blades, there is no opposite corner, so no rays to over lap. As a result, you can use the following formula's:

If an even number of blades, the number of rays is equal to the number of blades
If an uneven number of blades, the number of rays is double the amount of blades

The sharpness of the blades is also a good test to measure the sharpness of the lens when aperture is mostly closed.

Some Samples:

Starbursts caused by 4 blades

Starbursts caused by 7 blades

Starbursts caused by 6 blades

Starbursts caused by 8 blades

Sources:
B&H Photo Video: Create compelling star effects sun stars starbursts photos

Monday, 18 December 2017

The Value of Cheap - part 2: Nikon AF Nikkor 50mm 1.8 D

Cost: free ($132 new at B&H)

OK, I was very lucky here. My wife has used this lens for years as a semi-professional photographer on her Nikon D800. One day, the auto focus started failing, and due to the low cost for new, she decided to replace the lens instead of send it for repair, and hand the old lens to me. As the lens would only work manual on my camera, it was a great fit! This is one very nice lens.

Although it is also a lens in the budget friendly AF D series, it is much better build then the previously reviewed AF D zoom lens. It feels more dense, well constructed, but still a very light weight, small profile, lens. Focus and aperture rings work well, although not as smooth as some older lenses in the good old days. The aperture ring has a loud click, making this lens unsuitable for professional video.

Image quality is unchallenged. Some regard this lens as one of the sharpest lenses ever made by Nikon. For sure sharper than current, much more expensive (think < $2000) zoom lenses. Colors are great, good contrast and almost no distortion or color fringing. There is a reason that many professional photographers use this lens as one of their default lens, especially for low light photography.

Due to the quality, this lens is still manufactured and sold by Nikon. Yes, you can opt for a more expensive "G" quality lens, but your results will not be better. Maybe smoother handling, weather proofing, but in most cases, you save your dollars and by another lens in addition.

So, the value of cheap? In this case, very high, even if you have to pay full price. This lens will for sure go in "will use again' drawer. Hopefully soon!

Lens Specification:
Focal Length: 50mm
Maximum Aperture: F1.8
Minimum Aperture: F22
Image Format: 35mm
Lens Mount: NF
Optics:6 elements in 5 groups
Blades: 7
Focussing: Manual and Auto Focus on suitable camera
Minimum Focus: 45cm
Filter Size: 52mm
Weight: 157g
Length: 39mm
Production: 2007-now
Serial Number: 2692060
Made in: China

More information on Nikon Corporation

Samples:Taken with Viltrox NF to E-Mount Focal Reducer