SMC Pentax-M 1:1.7 50mm Asahi on K-5II (£26 purchase) - First Snaps

brandrx said:

brandrx wrote:

brandrx said:

Jenna B wrote:

brandrx said:

brandrx wrote:

When I have a manual focus zoom lens attached I will usually turn the SR off as long as I have enough light to keep my shutter speeds high enough. Sometimes I will just enter the SR focal length of the shortest focal length of the zoom so that I will always have some SR help. Sometimes, if I know that I am going to be shooting at the longer focal lengths of the zoom I might then enter a focal length somewhere near the center of the zoom focal lengths. If I know for sure that I will be using a certain focal length then I will enter that focal length for the SR.

Leave it at 2. That setting has no effect on anything other than when you have a manual focus lens attached that you will be using the aperture setting at the lens. IMO, Pentax should have simply set that setting to 2 from the beginning and never made it a choice. In other words, it is a useless menu setting to ever have it set to 1 in the first place.

Click to expand...

Thanks for confirming that, Ron, I had hoped it was just a pointless setting, makes things a lot easier to leave it set there! Might they perhaps have put the option in the menu as disabled in the first instance, so that people not used to manual lenses would be informed in some way that the lens was not auto-compatible, so to speak? I think this is a stretch... but trying to figure out the logic behind the decision (there must be some... surely?).

I know I am likely getting annoying with all my questions here, and am going slightly off topic with this one, but you are clearly very knowledgeable, so I will be cheeky Are cheap M42 screw mount lenses and other cheap (such as Vivitar and Tokina for example) lenses worth trying at all?

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There is usually a reason that they are cheap. With that being said, I use M42 lenses myself. Mostly the better Pentax SMC Takumar, and Takumar ones, such as 17mm fisheye, 20mm, 50mm f1.4, and 85mm f1.8. There are quite a few good to very good M42 lenses that are not Pentax Takumar lenses. I would suggest you ask in the forum about a specific lens to get the views of some of the very knowlegable folks.

brandrx said:

I have seen a Russian 1000mm mirror lens for £100 and a few 500mm f8 lenses on ebay for next to nothing, though I was concerned they'd be no better than the 55-300 cropped, in regards to IQ...

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Mirror lenses all have that dreaded donut bokeh. If you use them keeping in mind of your background and foreground then they can be used very effectivly. For instance shooting at a bird that is landed in the top of a tree, or a bird that has landed on a branch of some kind that there is no foreground and whatever background is very far behind the subject, or a waterbird that is in water that is not too choppy. There is little chance that donut bokeh will be a problem under those conditions.

Forum member MightyMike has used an 800mm f8 Rokinon mirror lens to effectivly shoot Red Bull airplane races. If I remember correctly he used catch-in-focus to make the image capture. One forum member used a 500mm f8 mirror on his trip to Africa and came back with some stunning images.

You will also get no CA's when using mirror lenses. Most of them can shoot quite effectivly up close for like a 1:3 Macro. However, you must at all times be aware of the donut bokeh. If the resulting image has just a little bit of donut bokeh then you can usually clone it out with software.

I have and occasionally use, 400mm, 500mm, 600mm, and 800mm mirror lenses. I don't think I would use any mirror that is slower than f8. I think most 1000mm and greater mirror lenses are f10 or smaller apertures.

As I wrote above about the M42 lenses, I would simply ask the forum members about a particular mirror lens that you have in mind of buying and trying. MightyMike in particular has made a study of mirror lenses and can impart quite good info to you if he sees your question.

FWIW: The 800mm f8 lens that I have is the same one that MightyMike has, the Rokinon 800mm f8. It is a T-mount and is usually sold with the mount that you require, else T-mount can be found usually for less than US $10. This mirror lens has a105mm filter thread. I bought the following 105mm metal lens hood to go on mine.

Desmond 105mm lens hood.

Either of the Tamron SP 500mm f8 Adaptall 2 mirror lenses (Model 55B or Model 55BB) are also good IMO.

Model 55B

Model 55BB

Cheers.

Ron

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brandrx said:

brandrx wrote:

brandrx said:

Thanks for the advice, Duncan

The genuine pentax adapter is about £45.00 here - I have found this cheaper one which claims to be able to focus to infinity still, is it worth a try? It's a fraction of the cost!

http://www.ebay.co.uk/itm/UK-M42-Le...ns_caps_hoods_adaptors_ET&hash=item3a6aa6153f

Click to expand...

That one is the kind with the flange and will not allow your lens to focus to infinity.

Cheers.

Ron

Click to expand...

Jenna B said:

Jenna B wrote:

Jenna B said:

brandrx wrote:

Jenna B said:

Jenna B wrote:

Jenna B said:

brandrx wrote:

When I have a manual focus zoom lens attached I will usually turn the SR off as long as I have enough light to keep my shutter speeds high enough. Sometimes I will just enter the SR focal length of the shortest focal length of the zoom so that I will always have some SR help. Sometimes, if I know that I am going to be shooting at the longer focal lengths of the zoom I might then enter a focal length somewhere near the center of the zoom focal lengths. If I know for sure that I will be using a certain focal length then I will enter that focal length for the SR.

Leave it at 2. That setting has no effect on anything other than when you have a manual focus lens attached that you will be using the aperture setting at the lens. IMO, Pentax should have simply set that setting to 2 from the beginning and never made it a choice. In other words, it is a useless menu setting to ever have it set to 1 in the first place.

Click to expand...

Thanks for confirming that, Ron, I had hoped it was just a pointless setting, makes things a lot easier to leave it set there! Might they perhaps have put the option in the menu as disabled in the first instance, so that people not used to manual lenses would be informed in some way that the lens was not auto-compatible, so to speak? I think this is a stretch... but trying to figure out the logic behind the decision (there must be some... surely?).

I know I am likely getting annoying with all my questions here, and am going slightly off topic with this one, but you are clearly very knowledgeable, so I will be cheeky Are cheap M42 screw mount lenses and other cheap (such as Vivitar and Tokina for example) lenses worth trying at all?

Click to expand...

There is usually a reason that they are cheap. With that being said, I use M42 lenses myself. Mostly the better Pentax SMC Takumar, and Takumar ones, such as 17mm fisheye, 20mm, 50mm f1.4, and 85mm f1.8. There are quite a few good to very good M42 lenses that are not Pentax Takumar lenses. I would suggest you ask in the forum about a specific lens to get the views of some of the very knowlegable folks.

Jenna B said:

I have seen a Russian 1000mm mirror lens for £100 and a few 500mm f8 lenses on ebay for next to nothing, though I was concerned they'd be no better than the 55-300 cropped, in regards to IQ...

Click to expand...

Mirror lenses all have that dreaded donut bokeh. If you use them keeping in mind of your background and foreground then they can be used very effectivly. For instance shooting at a bird that is landed in the top of a tree, or a bird that has landed on a branch of some kind that there is no foreground and whatever background is very far behind the subject, or a waterbird that is in water that is not too choppy. There is little chance that donut bokeh will be a problem under those conditions.

Forum member MightyMike has used an 800mm f8 Rokinon mirror lens to effectivly shoot Red Bull airplane races. If I remember correctly he used catch-in-focus to make the image capture. One forum member used a 500mm f8 mirror on his trip to Africa and came back with some stunning images.

You will also get no CA's when using mirror lenses. Most of them can shoot quite effectivly up close for like a 1:3 Macro. However, you must at all times be aware of the donut bokeh. If the resulting image has just a little bit of donut bokeh then you can usually clone it out with software.

I have and occasionally use, 400mm, 500mm, 600mm, and 800mm mirror lenses. I don't think I would use any mirror that is slower than f8. I think most 1000mm and greater mirror lenses are f10 or smaller apertures.

As I wrote above about the M42 lenses, I would simply ask the forum members about a particular mirror lens that you have in mind of buying and trying. MightyMike in particular has made a study of mirror lenses and can impart quite good info to you if he sees your question.

FWIW: The 800mm f8 lens that I have is the same one that MightyMike has, the Rokinon 800mm f8. It is a T-mount and is usually sold with the mount that you require, else T-mount can be found usually for less than US $10. This mirror lens has a105mm filter thread. I bought the following 105mm metal lens hood to go on mine.

Desmond 105mm lens hood.

Either of the Tamron SP 500mm f8 Adaptall 2 mirror lenses (Model 55B or Model 55BB) are also good IMO.

Model 55B

Model 55BB

Click to expand...

Fantastic info, thank you! I was hoping to use a long mirror lens to photograph the moon, as well as certain other celestial bodies (due to small aperture and movement, this would likely be at high ISO and shutter of 2 sec max, rather than slow shutter). I used to work in an optometrist, selling telescopes, amongst other things, and the mirror lenses remind me very much of the smaller schmidt and maksutov cassegrain scopes we used to sell for stargazing and spotting - I am hoping I may be able to purpose one in a similar way for near-earth stellar photography.

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Jenna B said:

I have put the Rokinon on my watch list, to remind me, thank you

Click to expand...

brandrx said:

brandrx wrote:
A full moon with no cloud obstructions is like shooting at the beach on a sunny day.

I think that when shooting the moon you need a shutter speed of at least 1/250s else you will have blur due to the movement of the moon in relation to the earth. You should have no problem getting at least 1/250s using an f8 lens. Someone can corrrect me if I am wrong.

brandrx said:

I have put the Rokinon on my watch list, to remind me, thank you

Click to expand...

MightyMike's first 800mm/8 went bad and he just bought another one via ebay for US $79. So, bide your time and don't pay those over US $200 asking prices that you see.

Cheers.

Ron

Click to expand...

Jenna B said:

Jenna B wrote:

Jenna B said:

brandrx wrote:

Jenna B said:

Thanks for the advice, Duncan

The genuine pentax adapter is about £45.00 here - I have found this cheaper one which claims to be able to focus to infinity still, is it worth a try? It's a fraction of the cost!

http://www.ebay.co.uk/itm/UK-M42-Le...ns_caps_hoods_adaptors_ET&hash=item3a6aa6153f

Click to expand...

That one is the kind with the flange and will not allow your lens to focus to infinity.

Click to expand...

Ah... so they lied! *shakes head* typical misinformation, should have known the price was too good to be true!

Looks like I'll have to save up £45.00...

Click to expand...

brandrx said:

brandrx wrote:

A full moon with no cloud obstructions is like shooting at the beach on a sunny day.

I think that when shooting the moon you need a shutter speed of at least 1/250s else you will have blur due to the movement of the moon in relation to the earth. You should have no problem getting at least 1/250s using an f8 lens. Someone can corrrect me if I am wrong.

Click to expand...