Which is optically better at 100mm? Pentax-A 100mm VS Soligor 70-220mm VS Pentax 50-200mm @100mm

Comparison of following three lenses at 100mm and f/5.6, f/8, and f/11:

• SMC Pentax-A 100mm f/4 Macro
• Soligor 70-220mm f/3.5 Macro at 100mm
• Pentax SMC DA 50-200mm f/4-5.6 at 100mm

Thoughts before the comparison 😊 :

Pentax-A 100mm f/4 has not been included in any comparison so far, so about time

I included Pentax SMC DA 50-200mm because at 100mm focal length, it was a better performer than Sigma 50-500mm. I excluded Sigma 50-500mm from this comparison for the same reason. As for Soligor 70-220mm f/3.5 Macro lens, it is a good performer at 220mm (better than Sigma 50-500mm) , but horrible at 135mm . So, how does it perform at 100mm? Lets see..

Comparison:

Set-up: Out-of-camera-jpegs; Same camera on tripod; Focus confirmation via OVF; no PP; Daylight WB in all photos; hood on all lenses.

F/5.6

Soligor f/5.6

DA 50-200mm f/5.6

Pentax-A 100mm Macro f/5.6

F/8

Soligor f/8

DA 50-200mm f/8

Pentax-A 100mm Macro f/8

F/11

Soligor f/11

DA 50-200mm f/11

Pentax-A 100mm Macro f/11

I would consider this test as valid as all three lenses are shifting the aperture and the ISO at each position.

Kent Gittings

The Soligar is bad. The zoom has higher contrast. The Macro is lower contrast but may be sharper at f/8+. I'm not sure but low contrast may be an advantage for macro?

chris gunn wrote:

The Soligar is bad. The zoom has higher contrast. The Macro is lower contrast ..

I agree. Soligor is horrible at this focal length. I'll try to compare both Pentax DA 50-200mm and Pentax A100mm Macro further with a different scene.

Further comparison of following two lenses at 100mm and f/4.5, f/5.6, and f/8:

• SMC Pentax-A 100mm f/4 Macro
• Pentax SMC DA 50-200mm f/4-5.6 at 100mm

Comparison:

Set-up: Out-of-camera-jpegs; Same camera on tripod; Focus confirmation via OVF; no PP; Daylight WB in all photos; hood on all lenses; no filter on any lenses.

F/4.5

50-200mm f/4.5

Pentax-A 100mm f/4.5

F/5.6

50-200mm f/5.6

Pentax-A 100mm f/5.6

F/8

50-200mm f/8

Pentax-A 100mm f/8

Seems massively different here. Strange?

chris gunn wrote:

Seems massively different here. Strange?

You mean 50-200mm's performance?

Massao wrote:

chris gunn wrote:

Seems massively different here. Strange?

You mean 50-200mm's performance?

The zoom looks OOF.

My impression:

Forget about the Soligor - at least if the aperture is almost open.

The Pentax zoom is OK. On the first sight and if you don't go the 100% view the Pentax zoom looks even better than the old Pentax macro - but things change at 100% view.

I would try to underexpose the photos with the Pentax macro and go into postprocessing with the RAWs.

Look at those parts of the photos where you have wood + gras in front. For the zoom lenses both parts drwon into a soup - but the Pentax macro clearly differentiates the subjects. This is what I want to see from a good lens and even though the Pentax lens is an old one it does a good job. For a better overall look (contrast, vibrancy, etc.) postprocesing would be the way.

Best regards

Holger

chris gunn wrote:

Massao wrote:

chris gunn wrote:

Seems massively different here. Strange?

You mean 50-200mm's performance?

The zoom looks OOF.

Thanks Chris; you are right! I think DA 50-200 doesn't focus properly on surfaces that are not too contrasty (like pink flowers, blue wall, or a brown lock). See here also--looks like same issue. I'll try to repeat the test by using manual focus on DA 50-200mm.

Holger Bargen wrote:

My impression:

Forget about the Soligor - at least if the aperture is almost open.

The Pentax zoom is OK. On the first sight and if you don't go the 100% view the Pentax zoom looks even better than the old Pentax macro - but things change at 100% view.

I would try to underexpose the photos with the Pentax macro and go into postprocessing with the RAWs.

Look at those parts of the photos where you have wood + gras in front. For the zoom lenses both parts drwon into a soup - but the Pentax macro clearly differentiates the subjects. This is what I want to see from a good lens and even though the Pentax lens is an old one it does a good job. For a better overall look (contrast, vibrancy, etc.) postprocesing would be the way.

Best regards

Holger

Thanks; I agree

Take 3: SMC Pentax-A 100mm Macro f/4 VS Pentax SMC DA 50-200mm

Different lighting conditions and double lens hoods. Since DA 50-200mm f/4-5.6 doesn't seem to focus accurately, I used manual focus this time.

F/4.5

DA 50-200mm f/4.5

Pentax-A 100mm f/4.5

F/5.6

DA 50-200mm f/5.6

Pentax-A 100mm f/5.6

F/8

DA 50-200mm f/8

Pentax-A 100mm f/8

Still a massive difference.