[benjikan]

Love this image Raybo!

Ben

[falconeye]

there can be an ever so slight focus shift, which I would put down to thermal expansion of the lens barrel.

Which is why some longer mirror lenses exist with carbon tubes.

[falconeye]

All the mirror lenses shown here look like 2.5 inch Schmidt-Cassegrain type scopes. Are there any Matsukov-Cassegrain type scopes offered as a tele lens?

An example of a 3.5 inch Matsukov-Cassegrain scope is the Celestron C90 Mak


However, mirror lenses for tele lens usage sometimes have a flat field corrector fo better edge sharpness. So, any Matsukov-Cassegrain tele lenses out there?

[Raybo]

IIRC, the (Russian made) MTO 1000mm and 500mm are Matsukov-Cassegrain.

Ray

[Raybo]

Here is another jpeg right out of the camera.

Cardinal at 48ft.



Ray

[ivoire]

I've been doing the opposite, shooting close up to fill the frame and check detail in an attempt to get better with this lens. heres a link to another forum thread and a pic with the tokina 500mm and a 1.5x tc for a 1125mm equivalent:

https://www.pentaxforums.com/forums/attachments/pentax-dslr-discussion/13125d...brd-large-.jpg

[Raybo]

I've been doing the opposite, shooting close up to fill the frame and check detail in an attempt to get better with this lens. heres a link to another forum thread and a pic with the tokina 500mm and a 1.5x tc for a 1125mm equivalent:

https://www.pentaxforums.com/forums/attachments/pentax-dslr-discussion/13125d...brd-large-.jpg

ivorie,

For what they are, I like the mirror lenses.

I'm not out for a "perfect" image, but the images I get work fine for my purposes, and I still have not cropped one image.

I'll post some images using the 500mm in the near future.


Ray

[ivoire]

ivorie,

For what they are, I like the mirror lenses.

I'm not out for a "perfect" image, but the images I get work fine for my purposes, and I still have not cropped one image.

I'll post some images using the 500mm in the near future.


Ray

Ray, really liked the woodpecker pic. That image i posted in the other forum is not cropped. it will print at around 24x17. I'm waiting for the sigma 600mm to arrive, tomorrow or by tuesday. I got hooked on these lenses and am enjoying. the shallow dof makes focusing tricky and i'm just now getting used to the tokina. look forward to your next post.

[benjikan]

Ben, it was your comment about using a mirror lens for a pro shoot that made me take a look for one. Most of the comments made me skeptical as it looked like this type of lens would be trouble. For $90, i think i got a decent lens. The tamron was among the highest rated but never seemed to come up when i looked. It is surprising that these lenses look almost identical. Looking forward to some of your posts with the Tamron.


Paul, i had no idea that these had a 'filter kit'. It is a very different way of shooting with this lens. the moon was shot manual and the others in av mode. controlling exposure requires some thought. now i will be looking for a lens kit after seeing Bens. Post a couple of pics when you have a minute.

The rear lens filters must be kept on the lens. The default filter is a Neutral Multi Layer Filter. The other 4 are obviously an ND, and B&W filters.

Ben

[barondla]

Nice moon shot Ivorie. Since ypu are shooting K20D put it on 3 second mirror lock up and use the wireless remote. Can make a world of difference. Most tripods don't settle down in 2 sec with that kind of magnification.
Remember to clean the front corrector plate differently than normal lens. Should make straight "spoke like" movements with the cleaning cloth. Not circular.
Questar used to make a Mak camera lens. Don't know if they still do. All their telescopes are Mak. These are expensive but as good as it gets for that type lens. Maks take longer for the optics to settle down in temp extremes.
Love my Celestron C5 (1250mm f10). Much better than the C90 I had. Old C90 didn't have the new multicoatings (star brite). Big deal with lower contrast mirror lenses. Have to post a shot with the lens when I get the time.
thanks
barondla

Enter POINT & SHOOT CONTEST #7 in P&S forum. Any type camera except slr. Any brand. Any subject. Today is last day! Enter now.

[ivoire]

Nice moon shot Ivorie. Since ypu are shooting K20D put it on 3 second mirror lock up and use the wireless remote. Can make a world of difference. Most tripods don't settle down in 2 sec with that kind of magnification.
Remember to clean the front corrector plate differently than normal lens. Should make straight "spoke like" movements with the cleaning cloth. Not circular.
Questar used to make a Mak camera lens. Don't know if they still do. All their telescopes are Mak. These are expensive but as good as it gets for that type lens. Maks take longer for the optics to settle down in temp extremes.
Love my Celestron C5 (1250mm f10). Much better than the C90 I had. Old C90 didn't have the new multicoatings (star brite). Big deal with lower contrast mirror lenses. Have to post a shot with the lens when I get the time.
thanks
barondla

Enter POINT & SHOOT CONTEST #7 in P&S forum. Any type camera except slr. Any brand. Any subject. Today is last day! Enter now.

barondla... thanks for the comment and the tips, will give it a try when moon is full. it appears that the sigma 600mm is lost in the mail. awaiting paperwork to file a claim. i'm hooked on mirror lenses and just bought a celestron c5 1250, so i'm happy to hear yours is working well. if i don't have more mail problems it should be here next week

ben... checked and it came with a skylight filter, no others. seems to be working well with the tokina

[barondla]

ivorie, I had a Sigma 600 with film oly. It was a nice lens. Wasn't as sharp as the C5! The C5 really surprised me on K10D/20D. No color problems. It is a big lens. Make sure you use a lens shade (Celestron makes a flat folding one with velcro that wraps around lens). Shade is about as long as lens! Thats a lot of glass up front so the shade really is needed. Did you get the optional tube to allow a camera to be used instead of the eyepiece? It requires a T adapter. Nice system that allows you to use any slr body on same lens.
thanks
barondla

Enter POINT & SHOOT CONTEST #7 in P&S forum. Any type camera except slr. Any brand. Any subject. Ends tonight!

[Adam67]

Ben,

I also have the Tamron SP 500mm. But I have just SP not the SP2; any idea what the difference is?

[ivoire]

ivorie, I had a Sigma 600 with film oly. It was a nice lens. Wasn't as sharp as the C5! The C5 really surprised me on K10D/20D. No color problems. It is a big lens. Make sure you use a lens shade (Celestron makes a flat folding one with velcro that wraps around lens). Shade is about as long as lens! Thats a lot of glass up front so the shade really is needed. Did you get the optional tube to allow a camera to be used instead of the eyepiece? It requires a T adapter. Nice system that allows you to use any slr body on same lens.
thanks
barondla

Enter POINT & SHOOT CONTEST #7 in P&S forum. Any type camera except slr. Any brand. Any subject. Ends tonight!

It is coming with a t mount to canon as the guy used it on his camera. i ordered a t to k mount adapter for it. i don't believe the lens hood/shade was included. will have to look into that. again, thanks for the advice. it looked like a monster lens, i'm looking forward to taking some moon shots with it.

[Raybo]

My 1000mm might have a little anomoly, if you look just to the right of the birds and about 20% down from the top of the image you will see a "spot".

It might need a cleaning, I checked for dust on the sensor and it came out clean.

Ray